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Exam 2
Biology 101
| Question | Answer |
|---|---|
| What are the 2 main phases of the cell cycle and what percent of the time does each cell spend in each? | Interphase 75%, M Phase 25% |
| what happens in G1 phase | growing, happens in interphase |
| what happens in S phase- | duplicate, happens in interphase |
| what happens in G2 phase - | double check, happens in interphase |
| what happens in Mitosis phase | begining of cell division, happens in M Phase |
| what happens in Cytokinisis phase- | Cell itself divided, happens in M Phase |
| In what phase of the cell cycle does the cell spend most of its time? | Interphase |
| What is cell division? | When a cell goes from one to two new daughter cells |
| Mitosis divided the _______? | Chromosomes |
| Cytokinesis divides the _______? | Cell itself |
| What is the difference between cytokinesis in plant cells and animal cells? | Plant- Form a cell plate in the middle of the cell to divide the cell into two cells Animal-bring the cell membranes in and then they pinch off |
| List the phases of mitosis in order they occur | Prophase, Metaphase, Anaphase, and Telophase |
| 1st phase of mitosis - Prophase | Centrioles move to opposite ends. Spindle fibers form, and chromosomes condense |
| 2nd phase of mitosis - Metaphase | Chromosomes attach to the spindle fibers and line up at the equator of the cell |
| 3rd phase of mitosis - Anaphase | Chromosomes are spereated by spindle fiber and chromatids go to the poles |
| 4th phase of mitosis - Telophase | Chromatides decondense back into chromatin and 2 new nuclear envelopes form. |
| What are Somatic cells? | Every cell in the body except for sex cells. These have 46 chromosomes and are diploid, and they are identical to one another |
| What are gametes? | Only sex cells can be gametes. the have 26 chromosomes and are hapliod, and they are different from one another. |
| What does it mean to be diploid? | You have 46 chromosomes |
| What does it mean to be Haploid? | You have 26 chromosomes |
| What are homologous chromoses? Where do you get them? | Pairs of the same chromosomes, one from the mother and one from the father. |
| Provide two ways in which Meiosis is different from Mitosis. | Meiosis is only assoicated with sexual reproduction. The number of cells created, type of cells that undergo this process, number of chromosomes and the number of times the cell divideds |
| Explain the events occuring in each phase of Meiosis I | Prophase I, Metaphase 1, anaphase 1, and telophase 1 |
| Metaphase I- | Chromosomes attach to the spindle fibers and line up at the equator of the cell |
| Anaphase I - | Chromosomes are spereated by spindle fiber and chromatids go to the poles |
| Telophase I | Chromatides decondense back into chromatin and 2 new nuclear envelopes form. |
| Explain the events occuring in each phase of Meiosis II | Prophase II - Spindle fibers reform, and centrioles move to opposite ends. |
| Metaphase II- | Spindle fibers attach and move to equator in a single file line |
| Anaphase II - | Spindle Fibers shorten and seperate, chromosomes into seperate chromitides and go to poles |
| Telophase II- | Four new nuclei form and cytokinesis follows |
| How many sperm and egg are made during meiosis? | Sperm-4, Egg-1 |
| The making of gametes is called_____? | meiosis |
| Describe the process of crossing over and why it is important. | Happens in Meiosis 1 when paired up with homologous chromosomes exchange genitic material with one another. Major source of genetic diversity in the species |
| What is a cell cycle regulator? What the different types? | Cyclin, internal regulator, external regulators. Any process that controls the series of events by which a cell goes through the cell cycle |
| Internal regulators - | proteins that respond to events inside the cell |
| External regulators - | proteins that respond to events outside the cell (e.g. growth factors) |
| Why do cells divide? | DNA "Overload"-Not enough information to run a big cell, Exchanging Materials-Must be able to eliminate wastes easily which can only happen if small, Ratio of Surface Area to Volume-Volume increases faster than the surface area |
| Exchanging Materials | Must be able to eliminate wastes easily which can only happen if small |
| What is Interphase? | Cell spends most of its time in interphase,cell grows, carries out basic cell functions,making organelles, and copy's chromosomes |
| What is M phase? | Where cell division happens, consists of Mitosis and Cytokinesis. Once the M Phase is finished, the cell cycle is complete and will begin again in the 2 newly formed daughter cells |
| What is the difference of Mitosis and Cytokinesis> | Mitosis is the division of the nucleus, while cytokinesis is the division of the cytoplasm |
| What is Prophase? | Mitosis begins, cells begins the process leading up to division, centrioles appear and move to opposite ends of the cell, spindle fibers form between these poles |
| What is Metaphase? | Chromatids (or pairs of chromosomes) attach to the spindle fibers |
| What is Anaphase? | Chromatids separate and move to opposite ends of the cell |
| What is Telophase? | Two new nuclei form ,Chromosomes appear as chromatin (threads rather than rods), Mitosis ends |
| What is uncontrolled cell growth? | Cells no longer respond to external regulators; some to internal regulators |
| What is cancer? | uncontrolled cell growth |
| What is a tumor? | cluster of cancer cells |
| What are sperm and egg also known as? | Gametes |
| What is sperm formation? | Where 4 haploid sperm cells are formed |
| What is egg formation? | Four cells are formed but most of the cytoplasm is used in one cell and the other three die. One haploid egg cell is formed. |
| What is Binary Fission? | Occurs in Prokaryotic Cells, DNA is copied and then the cell splits in half. |
| purine | double-ring nitrogenous base; adenine and guanine, always bonded to a pyrimidine called complimentary base pairing |
| a-site | the location on the ribosome where translation begins |
| mutation | change in the sequence of DNA; may occur due to replication error or damage caused by carcinogens |
| antiparallel | the term that indicates that the two complementary strands of DNA are running in the opposite directions. 5'------>3' or 3'------>5' |
| lagging | the _______ strand is copied discontinuously |
| initiation | the first step of translation |
| ribosome | organelle that is the site of protein synthesis; composed of RNA and protein |
| pyrimadine | single-ring nitrogenous base; thymine, uracil, and cytosine |
| RNA polymerase | the enzyme that adds nucleotides to a growing mRNA during transcription |
| adenine | the nitrogenous base that bonds with thymine or uracil |
| Griffith | scientist that showed that a "transforming factor" can be passed from one species of bacteria to another |
| exon | region of DNA that is part of a gene that will be expressed |
| complementary | adenine as it compares to thymine; cytosine as it compares to guanine |
| s phase of interphase | time during cell cycle when DNA replicates |
| gene | unit of heredity existing at a particular location on a chromosome; codes for a functional product, usually a protein |
| chromosome | structure containing many genes in specific locations and composed of tightly wound DNA and histones |
| intron | region of DNA that is not part of a gene |
| methionine | the amino acid associated with a "start" codon (AUG) |
| triphosphate | type of molecule that provides the energy for the nucleotide polymerization; nucleotide _________ |
| ligase | the enzyme that connects Okazaki fragments |
| semiconservative | the term that recognizes that the daughter strands each received 1/2 of the parental strand but are also composed of a newly constructed strand |
| Watson | the last name of the American member of the pair of scientists who modeled the structure of DNA |
| nucleolus | site of ribosome synthesis in eukaryotes |
| primary transcript | mRNA before processing |
| 15% | if the percentage of thymine in a cell is 35%, what is the percentage of guanine? |
| phosphate | the molecule attached to the 5' carbon of a ribose or deoxyribose of a nucleotide |
| nucleotide | the monomer of DNA and RNA; consists of a sugar, phosphate, and a nitrogenous base |
| euchromatin | DNA that is unwound, and spread out in the nucleus; the form that DNA takes as it is replicating or being transcribed |
| DNA helicase | the enzyme that unwinds and unzips DNA so it can replicate |
| Chargaff | the last name of the German chemist who noticed that the amount of adenine is always equal to the amount of thymine and the amount of cytosine is always equal to the amount of guanine, no matter what type of cell |
| DNA polymerase | the enzyme that adds nucleotides to a growing daughter strand during replication |
| alternate splicing | the process that results in more than one protein per gene |
| protein | the type of molecule that DNA codes for; constructed of amino acids; polypeptide |
| guanine | the nitrogenous base that forms three hydrogen bonds with cytosine; a purine |
| leading | the ________ strand is copied continuously |
| nitrogenous base | the molecule attached to the 1' carbon of a ribose or deoxyribose of a nucleotide; purine or pyrimidine |
| hydrogen | the type of weak bond that connects complementary nitrogenous bases; two between A & T, three between G & C |
| dehydration synthesis | type of reaction that links amino acids to form a protein AND nucleotides to from a nucleic acid; sometimes called a condensation reaction (also the type of reaction that links triphosphate nucleotides to form nucleic acids) |
| Okazaki fragments | the disconnected pieces of the lagging strand of DNA |
| Rosalind Franklin | the woman whose x-ray crystallography helped identify the structure of DNA |
| Gregor Mendel | proved that traits are passed from parent to offspring in predictable fashion |
| mRNA | the type of RNA that carries amino acids to a ribosome in the cytoplasm |
| promoter region | region of DNA where RNA polymerase first binds to begin transcription |
| insertion | a mutation involving the addition of one or more nucleotides, resulting in a frameshift |
| lymph nodes | organs of the lymphatic system that filter fluids deposited by the circulatory system; if cancer is detected here, it indicates metastasis has occurred |
| malignant | tumors that have invaded the surrounding tissue or metastasized; cancerous |
| transposons | DNA sequences that can move within the genome |
| metastasis | tumor cells migrate and spread cancer to additional locations |
| enhancer | region of DNA preceding some genes where transcription activators can bind to increase the rate |
| carcinogen | a mutagen that causes cancer |
| biopsy | the surgical removal of cells, tissue, or fluid for analysis to determine if cancer is present |
| mutagen | a substance that causes a mutation |
| substitution | mutation in which one nucleotide is exchanged for another; effect varies |
| benign | a tumor that has not metastasized or invaded surrounding tissue; non-cancerous |
| silent | mutation in which the changed codon results in the same amino acid |
| telomere | sequence of DNA at tips of chromosomes that limits the number of times a cell can divide |
| cancer | disease resulting from multiple mutations, especially of genes that control cell division |
| tumor | a pile-up of cells that is the result of uncontrolled cell division |
| point | a mutation involving only one nucleotide |
| DNA | Deoxyribonucleic Acid, genetic material of life. A polymer of nucleotides. |
| Confirmed DNA as the genetic material | Hershey and Chase 1950's |
| DNA replication | the process of copying one DNA double helix into two identical double helices; occurs during Synthesis phase of cell cycle |
| Transfer RNA also known as tRNA | transfers amino acids to the ribosomes to form proteins. |
| Ribosomal RNA (rRNA) | joins with proteins made in the cytoplasm to form the subunits of the ribosomes. |
| Gene Expression | process of using a gene sequence to synthesize a protein. Includes two process called transcription and translation. |
| Uracil | nitrogen base that occurs in RNA in the place of thymine. |
| Three steps required in translation | initiation, elongation, and termination |
| Euchromatin | active genes in eukaryotic cells are associated with loosely packed chromatin. |
| Codon | three-nucleotide sequence on messenger RNA that codes for a single amino acid |
| Translation | is the second process by which gene expression leads to protein synthesis. |
| anticodon | group of three bases on a tRNA molecule that are complementary to an mRNA codon |
| poly-A tail | a sequence of 50-250 adenine nucleotides added onto the 3' end of a pre-mRNA molecule |
| primary transcript | The initial mRNA transcript that is transcribed from a protein coding gene. Also called pre-mRNA. |
| alternate splicing | building different proteins by combining exons of a gene in different ways; results in >1 protein/gene |
| Epigenetics | the study of influences on gene expression that occur without a DNA change |
| Methylation of cytosine | causes transcription to permanately stop for that gene, turns genes off, ex. barrebody is an inactive x chromosome which are highly methylated |
| acetylation of histones | Unwinds DNA, adds actyl group- changes shape = genes turned ON |
| missense mutation | A point mutation in which a codon that specifies an amino acid is mutated into a codon that specifies a different amino acid. |
| nonsense mutation | A mutation that changes an amino acid codon to one of the three stop codons, resulting in a shorter and usually nonfunctional protein. |
| guanine cap | post transcription modification that protects 5' end of mRNA and facilitates binding to the ribosome |
| frameshift mutation | mutation that involves the insertion or deletion of a nucleotide in the DNA sequence, resulting in all subsequent codons being changed |
| posttranslational control | Control of proteins that are already made. Ex: activate, deactivate or degrade the protein |
| transcriptional control | RNA is only made for some genes, due to regulatory proteins at the promoter (transcription factors) |
| Telomerase | An enzyme that catalyzes the lengthening of telomeres in eukaryotic stem cells and some tumor cells |
| what does cell division increase? | number of somatic cells (body cells) |
| zygote | single cell |
| apoptosis | programmed cell death |
| characteristics of apoptosis | - decreases # of cells, - occurs during development to remove unwanted tissue, - important in preventing cancer |
| apoptosis examples | - tail of tadpole, - webbing between human fingers and toes |
| cell cycle | Orderly set of stages that occur between the time a cell divides and the time the resulting daughter cells divide |
| interphase | - G1, S (DNA replication, G2 |
| mitotic stage | mitosis (division of nucleus) and cytokinesis (division of cytoplasm) |
| what tightly controls the cell cycle? | checkpoints -> healthy cell division |
| what do failed checkpoints cause? | cancer development |
| a damaged cell should not complete mitosis, instead.... | should undergo apoptosis |
| carcinogenesis | development of cancer |
| characteristics of carcinogenesis | - multi step process- involves disruption of cell division & behavior- mutation initiates cancer |
| mitosis | a nuclear division in which chromosome number stays constant |
| where does mitosis occur? | somatic cells -> body growth |
| process of mitosis | centromere divides and each chromatid becomes a daughter chromosome (sister chromatids genetically identical) |
| cell division- karyokinesis | division of nucleus |
| cell division- cytokinesis | division of cytoplasm |
| stages of mitosis- prophase | - chromosomes condensed- spindel fibers appear, mitosis begins, cells begins the process leading up to division, centrioles appear and move to opposite ends of the cell, |
| stages of mitosis- metaphase | - nuclear membrane disappears- each centromere attached w/ spindle fibers- chromosomes arranged at equator |
| anaphase | v- shaped chromosomes drag to poles |
| telophase | - chromosomes occupy two ends- spindle disappears- nuclear envelope begins to organize- last step in karyokinesis |
| cytokinesis | division of cytoplasm follows the karyokinesis (division of nucleus)- cell membrane pinches inward producing 2 daughter cells |
| meiosis | -reduce # of chromosomes- occurs in life cycle of sexually reproducing organisms- provides offspring w/ different combo of traits from that of either parent |
| phases of meiosis- prophase 1 | - homologues line up side-by-side at equator (synapsis)- cells are now haploid- when pairs separate, each daughter cell receives one member of the pair |
| phases of meiosis- metaphase 1 | - characterized by alignment of chromosome pairs at equator in several ways- results in re-assortment of chromosomes |
| follow meiosis- anaphase I | homologous chromosomes separate out with the new parts |
| follow meiosis- telophase I | end of nuclear division(cytokinesis may/may not follow) |
| meiosis II | - no replicatio of DNA occurs between meiosis (I and II)- centromeres divide and sister chromatids migrate to opposite poles to become individual chromosomes- each of 4 daughter cells has the haploid chromosome # |
| interkinesis | Period of time/rest between meiosis I and meiosis II during which no DNA replication takes place. |
| what follows interkinesis? | prophase II, metaphase II, anaphase II (where chromatids move to different poles), telophase II (end of nuclear division II), cytokinesis occurs |
| consequences of meiosis | - genetic recombination occurs in 2 ways (crossing over and independent assortment)- helps ensure genetic variation |
| what process maintains the chromosome number? | mitosis |
| what process reduces the chromosomes in daughter cells? | meiosis |
| what process results in two daughter cells? | mitosis |
| what process results in four daughter cells? | meiosis |
| in what type of cells does mitosis occur? | somatic (body) cells |
| in what type of cells does meiosis occur? | reproductive cells that form gametes (sperms and eggs) |
| daughter cells from mitosis | genetically identical to each other and to the parent cell |
| indicate a non-dividing phase, which prepares the cell for division? | interphase |
| apoptosis causes a cell to ___? | die |
| karyokinesis is the division of ___? | nucleus |
| mitosis occurs in somatic cells having _____? | two sets of chromosomes |
| you can count the chromosome number in ____? | metaphase |
| telophase marks the ____ of nuclear division? | end |
| what reduces/divides in meiosis I? | chromosome |
| meiosis occurs during the formation of ____? | sperms and eggs |
| DNA replication occurs in the _____ of Interphase? | S phase |
| The ____ gene helps to prevent cancer by coding for proteins that check the DNA and stop cell division if the DNA is damaged. | p53 |
| Somatic cells are | body cells, and able to undergo mitosis |
| The cell cycle is a set of orderly stages that occurs between | one cell division and the next. |
| At the conclusion of apoptosis, a cell fragments, and its pieces are engulfed by | white blood cells. |
| Signals that tell a cell whether or not to divide are more likely to be | external signals. |
| Body cells, which are cells that do not undergo meiosis to become sperm or oocytes, are also called | somatic cells |
| The repeating sequence of events in eukaryotes that involves cell growth and cell division is called the | cell cycle |
| A cell rounds up and loses contact with its neighbors at the beginning of | apoptosis |
| Signals that ensure that stages of the cell cycle follow one another in the normal sequence are more likely to be | internal signals. |
| Choose ALL possible outcomes in a cell that cannot pass the G1 checkpoint because its DNA is damaged | .The p53 protein will attempt to initiate DNA repair. Apoptosis will occur if the DNA cannot be repaired. The cell may move into G0 if DNA repair is not possible. |
| The influence of what two types of genes determines if cell division does or does not occur? | tumor suppressor genes and proto-oncogenes |
| Eukaryotic chromosomes are composed of _____________, which is a mixture of DNA and protein. | Chromatin |
| In humans, mitosis produces cells that are | diploid |
| Damaged DNA in a cell can prevent the cell from passing which of the checkpoints? | G1 |
| Proto-oncogenes and tumor suppressor genes control the movement of a cell through the | cell cycle. |
| A cell organelle that occurs in the centrosome and helps organize a mitotic spindle for chromosome movement during animal cell division is called a(n) | centriole |
| Mitosis produces daughter cells that have the same number of chromosomes as the | parent cell. |
| __________ begins during the anaphase of mitosis and is completed just before the cell enters the next interphase to prepare for a new division. | Cytokinesis |
| _______ is a type of nuclear division that occurs as a part of sexual reproduction, and the resulting daughter cells have a haploid number of chromosomes, which is 23 in humans. | meiosis |
| Which of the following is true about a homologous chromosome pair? | One came from the female parent and one from the male parent. |
| The first phase of meiosis is | prophase 1 |
| Centrioles are a type of microtubule organizing center found only in | animal cells |
| True or false: Cytokinesis begins in anaphase and continues in telophase, reaching completion just before the next interphase of the cell cycle. | True |
| The spindle forms, chromosomes condense, the nuclear envelope fragments, the nucleolus disappears, homologous chromosomes pair up, and crossing-over occurs during | prophase 1 of meiosis 1 |
| Meiosis produces genetic variation among gametes by way of which of the following events? | independent assortment, crossing over |
| Select all of the following that describes meiosis | Cytokinesis results in four daughter cells. Daughter cells are haploid. |
| Within most tissues of the human body, a process called_________ occurs to produce more cells. | mitosis |
| In meiosis, crossing-over occurs during prophase I and results in | new mixtures of genes; |
| while during metaphase I, independent assortment results in | new mixtures of chromosomes. |
| What describes the outcome of mitosis? | daughter cells with the same chromosome number as the parental cell |
| The three events that distinguish meiosis from mitosis are | the separation of homologous chromosomes. homologous chromosomes synapse. crossing over. |
| In the human life cycle, meiosis produces _________, and________ continues throughout life for growth, development, and tissue repair. | gametes, mitosis |
| In human females, the process of oogenesis results in the production of | eggs |
| What event occurs in meiosis but not mitosis? | Crossing over |
| In humans, a zygote undergoes what process to form a fetus and then a child? | Mitosis |
| Describe the major events that occur during each stage of the cell cycle. | During G1, the cell increased the number of organelles and increased in size. In the S state, DNA replications occurs and the genetic material is duplicated. In the G2 stage, the cell prepares for cell division. In the M stage, cell division and cytokines |
| Explain why apoptosis is a necessary process. | It removes unwanted tissue and abnormal cells. |
| Explain what factors would cause a cell to stop at each of the 3 cell cycle checkpoints. | Cells stop at the G1 checkpoint if conditions are not favorable for cell division and/or there is DNA damage. Cells stop at the G2 checkpoint if the DNA has not finished replicating and/or there is DNA damage. Cells stop at the M checkpoint if the chromos |
| Summarize the importance of growth factors in regulating the cell cycle. | Growth factors are external signals that promote the cell division of target cells. |
| Distinguish between the action of oncogenes and mutated tumor suppressor genes. | Oncogenes encode proteins that continuously promote the cell cycle, leading to unregulated cell division. Tumor suppressor genes function to inhibit the cell cycle. If mutated, the proteins they express would not be active and the cell cycle would continu |
| Distinguish between the number of chromatids each chromosome contains before and after replication. | One chromatid before replication and two chromatids after. |
| Summarize the events that are occurring in each stage of mitosis. | PMAT |
| mitosis - P- | Centrioles move to opposite ends. Spindle fibers form, and chromosomes condense. |
| mitosis M- | Chromosomes attach to the spindle fibers and line up at the equator of the cell. |
| Mitosis - A- | Chromosomes are spereated by spindle fiber and chromatids go to the poles. |
| Compare and contrast cytokinesis in plant and animal cell. | Both result in 2 daughter cells with identical genetic material. Animal Cells form a cleavage furrow between the daughter nuclei, which is constricted by the action of a band of actin filaments. Plant cells build a new cell wall between the daughter cells |
| Explain why there are 2 divisions in meiosis and why the DNA is not replicated between meiosis 1 and meiosis 2. | This is done to divide the DNA content in half. The DNA is not replicated between meiosis 1 and meiosis 2, because the DNA was already replicated before meiosis began. |
| Outline the major events that occur during meiosis 1 and 2, focusing on the activities of the chromosomes. | Meiosis 1: helps ensure that genetic variation of the parental gene occurs though crossing over and independent assortment. Meiosis 2: Each duplicated chromosome attaches to the single and they align at metaphase, sister chromatids separate, becoming daug |
| Meiosis 1: | helps ensure that genetic variation of the parental gene occurs though crossing over and independent assortment. |
| Meiosis 2: | Each duplicated chromosome attaches to the single and they align at metaphase, sister chromatids separate, becoming daughter chromosomes that move into nuclei. |
| Explain how crossing-over and independent assortment introduce genetic variation. | During crossing-over, genetic material is exchanges between nonsister chromatids. This produces a different combination of genes. Independent assortment mixes the whole chromosomes donated by both parents. The end result of both processes is cells that do |
| Describe the differences in the activity of the homologous chromosomes in prophase and metaphase of meiosis 1 and mitosis. | Metaphase-meiosis 1: tetrads lines up on the middle. Metaphase - mitosis: double chromosome line up on the middle. |
| Compare and contrast the outputs of meiosis and mitosis with regard to the number of cells and the chromosome complement of each cell. - | Mitosis has only one round of cell division, while meiosis has two. Mitosis only occurs in somatic (body) cells, while meiosis occurs in sex cells. Mitosis produces daughter cells (diploid cells) that are identical to the parent cell, while mitosis produc |
| New synthetic nucleotides have been inserted into E. coli bacteria to | increase the number of amino acids they can produce, which can help with the development of new drugs and other applications. |
| Select the reasons why early molecular geneticists knew that the genetic material needed to be a stable molecule. | It must be able to pass from one generation to the next. It needs to be replicated accurately. |
| In the 1940s, scientists had concluded that the genetic material was most likely | either protein or DNA. |
| True or false: A purine base normally pairs with a pyrimidine base. | True |
| The synthesis of new DNA double helix molecules from a pre-existing parent molecule is called | DNA replication. |
| Which of the following are the two new nucleotides that have been created by the company Synthorx? | X, Y |
| The process by which an RNA strand is synthesized from a DNA template strand is called | transcription. |
| Select the characteristics researchers suspected the genetic material would have prior to the discovery that the genetic material was DNA. | accurate replication, passes from one generation to the next, ability to store information |
| In the 1940s, why was protein considered to be the source of genetic material? | Proteins contain 20 amino acids that can be sequenced in a variety of ways. |
| Which molecule carries genetic information from the DNA to the ribosome? | mRNA |
| The production of two DNA copies from a single original DNA molecule is called | DNA replication. |
| The specific type of nucleic acid bearing anticodons complementary to codons is abbreviated | tRNA |
| The production of mRNA from a DNA template occurs during | transcription |
| Select the stages of translation. | Termination, initiation, and elongation |
| The purpose of mRNA is to carry information from DNA to the | ribosomes. |
| Transcription and translation are two stages in the process of | gene expression. |
| Select the characteristics of translation. | involves ribosomes, results in a protein product, involves an mRNA molecule |
| Which nucleic acid is the physical carrier of individual amino acids? | tRNA |
| The expression of selected genes accounts for the specialization of cells like | white blood cells, muscle fibers, and nerve cells. |
| The process by which an RNA strand is synthesized from a DNA template strand is called | transcription. |
| Rank the phases of translation in order of occurrence, beginning with the first phase at the top. | Initiation, elongation, and termination. |
| The production and usage of a gene's product is called | gene expression |
| What structure consists of a set of prokaryotic genes for proteins with related functions? | Operon |
| Which of the following are true of both transcription and translation? | stage in gene expression, mRNA is involved, occur in eukaryotes and prokaryotes |
| Genes that are active in most of the body's cells are called | housekeeping genes. |
| The production of mRNA from a DNA template occurs during | transcription. |
| A primary difference between control of gene expression in prokaryotes and eukaryotes is that | prokaryotes have fewer promoters than they have genes |
| A cluster of genes that codes for proteins related to a particular metabolic pathway is called a(n) | operon |
| A certain gene excerpt has the sequence AAGGGTAACGA, then changes to CCGGGTAACGA. What just happened? | Gene mutation |
| Which organism would have the most complex control of gene expression? | Fungi |
| Chemical or physical agents that increase the chance of mutation are called | mutagens |
| A mutation that results in one base in the DNA being replaced by a different base is called a | point mutation |
| A gene mutation is a_________ change to the base sequence of DNA. | permanent |
| A tumor that is not cancerous is called | benign |
| Select the choices that describe mutagens. | cause changes in DNA base sequences, can be physical, like radiation, or chemical, are environmental factors |
| True or false: Cancer cells undergo apoptosis as regularly as normal cells | False |
| What is example of a point mutation? | Base substitution. |
| Most cancers begin as an abnormal cell growth or tumor that is referred to as benign, or not cancerous, and usually | does not grow larger |
| Which of the following are characteristics of cancer cells? | escape signals for death, genetically unstable, promote angiogenesis, exhibit metastasis |
| Explain why DNA replication is said to be semiconservative. | A new double strand of DNA comprises one old strand and one newly synthesized strand. |
| Summarize the sequence of events that occur during DNA replication. | 1. The enzyme DNA helicase unwinds and unzips the double-stranded DNA by breaking the weak hydrogen bonds between the paired bases. 2. New complementary DNA nucleotides, always present in the nucleus, fit into place by the process of complementary base pa |
| Could you explain the role of mRNA, tRNA, and rRNA in gene expression? | mRNA carries the genetic information encoded in DNA from the nucleus to the ribosomes in the cytoplasm. At the ribosome composed of rRNA and proteins, mRNA assemble amino acids carried by tRNA into chains, which are eventually released to for functional p |
| Describe the movement of information from the nucleus to the formation of a functional protein. | The information stored in DNA is transcribed into mRNA which then, with the help of tRNA at the ribosomes made of rRNA, translated the information into protein structure. |
| Discuss why the genetic code is said to be deaerated. | The genetic code contains more than one triplet codon for each amino acid. |
| Explain why gene expression would not be the same in all cells of an organism. | Different cellar subject to different controls of gene expression, such as X-inactivation and pretranscriptional, transcriptional, posttracscriptional, translational, and posttranscriptional control. |
| Describe how the lac operon represent an on/off switch for gene expression. | In the absence of lactose, a repressor is bound to the promoter/operator complex and no lactase is produced. Lactose will bind to the repressor and prevent it from binding to the operator. The gene for lactase can then be expressed. |
| Summarize the different levels of gene regulation in eukaryotes. | 1- pretranscriptional control- Chromatin stays packed; 2-transcriptional control - factors that speed up transcription; 3- posttranscriptional control - introns removed and exons joined varies among cell types. ; 4- translational - Hormones extend the lon |
| pretranscriptional control- | Chromatin stays packed |
| transcriptional control - | factors that speed up transcription |
| posttranscriptional control - | introns removed and exons joined varies among cell types. |
| translational - | Hormones extend the longevity of the mRNA, meaning more of a specific polypeptide is produced. |
| posttransitional control- | occurs in cytoplasm -protein inactive - need to be activated |
| Explain how gene mutations occur. | Gene mutations can happen when DNA replication produces errors, when a mutagen causes physical damage toDNA, and when transposes jump into a new location, disrupting the neighboring genes. |
| Distinguish between a point mutation and a frameshift mutation. | A point mutation occurs when one DNA nucleotide is changed. A frame shift mutation occurs when a nucleotide is inserted or deleted. |
| A point mutation | occurs when one DNA nucleotide is changed. |
| A frame shift mutation | occurs when a nucleotide is inserted or deleted. |
| Explain the characteristics of cancer cells. | Cancer cells have high levels of mutagenesis and disregulated cell cycles. They avoid apoptosis and can metastasize. |
| Prophase I - | Centrioles move to opposite ends. Spindle fibers form, and chromosomes condense |
| Prophase II - | Spindle fibers reform, and centrioles move to opposite ends. |
| Cyclin - | a protein which regulates the cell cycle |
| Mitosis. T- | Chromatides decondense back into chromatin and 2 new nuclear envelopes form. |
Created by:
Keelee