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Bio 105 Exam 3
| Question | Answer |
|---|---|
| What are the 3 rules to Cell Theory? | All organisms are composed of cells, all cells come only from pre-existing cells, and cells are the smallest structural and functional unit of organisms |
| Gene definition | Segment of DNA that encodes a protein, made of hundreds to thousands of nucleotides |
| Chromosome definition | Very long strand of DNA and proteins that carry genetic information, has histones (proteins), one chromosome has many genes on it, each species has a specific number of chromosome |
| Histone definition | Protein in a chromosome that wraps and coils (structural support) |
| Diploid (2n) definition and example | Cells (organisms) that have 2 copies of each chromosome, example: humans --> 23 different types of chromosomes, 2 copies of each (from parents), total: 46 chromosomes, 2n = 46 |
| The Cell Cycle definition | Cyclical, ordered set of stages that takes place as a cell grows and divides (2 major steps) |
| Interphase definition | First phase of the Cell Cycle, how a cell typically spends most of its time, cell is doing its regular function, prepares for cell division, replicates DNA (2 copies of each chromosome), number of organelles doubles |
| Mitotic Stage (Cell Division) end result and name of processes | Second phase of the Cell Cycle, results in two genetically identical daughter cells, has mitosis and cytokinesis stages |
| Mitosis definition and name of processes | Division of DNA in nucleus, 4 steps (Prophase, Metaphase, Anaphase, and Telophase) |
| Prophase definition | First step in Mitosis, DNA condenses, visible under a microscope, each duplicated chromosome is made up of 2 sister chromatids, nuclear envelope is breaking down |
| Metaphase definition | Second step in Mitosis, chromosomes line up in middle of cell |
| Anaphase definition | Third step in Mitosis, sister chromatids pull apart |
| Telophase definition | Last step in Mitosis, two clusters of chromosomes will become nuclei |
| Cytokinesis definition | Last step of the Cell Cycle, division of cytoplasm and organelles |
| 2 reasons why the Cell Cycle occurs | Growth and repair |
| What are Cell Cycle checkpoints | Checkpoints at key transitions between stages, highly regulated, prevents skipping and premature cell division, if a cell fails a checkpoint apoptosis occurs, if there is a problem in the cell cycle, cancer can occur |
| Apoptosis definition | Programmed cell death |
| Estimates of cancer in 2023 in the U.S. | 2,000,000 people diagnosed with cancer, 600,000 people die of cancer, worldwide, cancer is among the leading causes of death |
| Cancer definition | Cancer is your cells out of control, DNA genes are mutated so proteins are not controlling cells properly, no programmed cell death --> your cells, so ignored by immune system |
| Development of cancer in an organism | Tends to be gradual, may take years before a cell is obviously cancerous, non-specialized, immortal cells, uncontrolled cell cycle, form tumor |
| Tumor definition | Abnormal growth of cells |
| Benign (tumor) definition | Not harmful, doesn't spread |
| Malignant (tumor) definition | Cancerous, invades surrounding tissue, can metastasize (move), dangerous |
| 5 Cancer cell characteristics | Large, variably shaped nuclei, many dividing cells; disorganized arrangement, variation in size and shape, loss of normal features, forms new blood vessels |
| 4 Stages of cancer | Stage 1: Localized, Stage 2: Locally advanced (early), Stage 3: Locally advanced (late), Stage 4: Metastasized |
| Who was Henrietta Lacks? | Died of cervical cancer that metastasized, biopsy of her tumor before death, first successful immortal human cells to grow in lab, used for lots of research, helped lead to regulations on consent and use of human tissue for experiments |
| 5 Causes of cancer | Mutations, hereditary, radiation sources, pesticides and herbicides, viruses |
| Difference of cells in cellular and organismal reproduction | In Mitosis, one cell splits and forms two genetically identical cells. In Organismal Reproduction, it is one generation to the next (parents and offspring) and results in genetic variation, or genetically different cells |
| Animals are ____? | Diploid (Two of each chromosome; 2n) |
| Homologous Chromosomes (Homologs) definition | Two chromosomes of the same type, one from each biological parent, same genes present, but the exact DNA sequence for those genes could be different |
| Allele definition and example | Variation of a gene, different DNA, different chains of amino acids, same type of protein produced but with slight differences , example: Allele B: ATGTGTTGCGTAGTA (Portion of a gene) --> Allele b: ATGTGTCGTA (Portion of a gene) |
| Genotype definition and example | Alleles of an organism (Genetic information), example: AA and aa, determines the phenotype |
| Phenotype definition and example | The physical traits of an organism, example: White vs black lab |
| Gamete definition | Reproductive cells; in human egg and sperm, are haploid |
| Haploid (n) definition | One of each chromosome, important for sexual reproduction because we can remain diploid organisms when genes are passed onto offspring |
| Process of gametes in sexual reproduction | Parents --> 2n, Gametes --> n, Gametes (2) fuse --> 2n, during fertilization, zygote grows and develops into next diploid generation |
| Meiosis definition, input, and outputs | Cell division that makes cells with one copy of each chromosome (n), important for making gametes, start with one 2n (diploid) cell --> End with four genetically different n (haploid) cells, 2 Stage process (chromosomes duplicated already |
| Meiosis I definition | First step of Meiosis, homologous chromosomes separate, 4 step process |
| Prophase I definition | First step of Meiosis I, homologous chromosomes align side by side, crossing over can occur |
| Metaphase I definition | Second step of Meiosis I, homologous line up in center (middle) |
| Anaphase I definition | Third step of Meiosis I, jomologous chromosomes separate, (Diploid --> Haploid) |
| Telophase I and Cytokinesis definition | Last step of Meiosis I, each cell has 1 copy of chromosome |
| Meiosis II definition | Last step of Meiosis, sister chromatids separate, 4 haploid cells produced, 4 step process |
| Prophase II definition | First step of Meiosis II, chromosomes condense |
| Metaphase II definition | Second step of Meiosis II, chromosomes align in middle |
| Anaphase II definition | Third step of Meiosis II, sister chromatids separate |
| Telophase II and Cytokinesis definition | Last step of Meiosis II, four haploid cells all genetically unique |
| Importance of Genetic Variation in Meiosis | Meiosis introduces genetic variation, important for populations to persist and respond to environmental changes, allows species to evolve and adapt |
| 2 Ways Genetic Variation can occur | Independent Assortment and Crossing-Over |
| Independent Assortment definition and how it occurs in humans | Homologous chromosomes align randomly in metaphase I, mixes up DNA in gametes, humans have 23 pairs of chromosomes --> 2^23 or 8,288,608 gamete combinations (A lot of variation), offspring are (2 ^ 23) 2 or > 70 trillion combinations |
| Crossing-over definition and how it occurs in humans | Exchange of DNA between non-sister chromatids, occurs in meiosis I (prophase I), new combinations of alleles, (4 ^ 23)2 unique offspring genotypes |
| Nondisjunction definition and when it can occur | Failure of chromosomes to separate, leads to the loss or gain of chromosomes in daughter cells, can occur in Meiosis I or II |
| Euploidy definition | Correct number of chromosomes in a person |
| Aneuploidy definition | Change in diploid chromosome number |
| Monosomy definition | 1 chromosome |
| Trisomy definition and syndrome it is related with | 3 of same chromosome, extra chromosomes, Trisomy 21 (Down syndrome) --> 3 chromosomes #21 |
| Chromosomes in humans that can change while not hindering our ability to function | In humans, only viable for chromosome 21 and 'sex' chromosome (if these have a change in the number of chromosomes, human can still function) |
| Deletion definition | Section of chromosome detaches |
| Duplication definition | Section of chromosome duplicates |
| Inversion definition | Section of chromosome flips around (Order of sections is mixed up) |
| Translocation definition and syndrome example | Ends of chromosome switch with another chromosome, example: Williams Syndrome --> loss of the end of chromosome 7, unrelated children have similar appearance, health, and behavioral problems |
| Genetics definition | The study of heredity and the variation in inherited characteristics, explains the stability of inheritance and the variation between generations |
| Process of how DNA genes make Proteins | (Genotype) DNA gene --> (transcription) RNA --> (translation) Proteins (Phenotype), small change in DNA sequence --> slightly different biochemical abilities; different phenotype |
| Phenotype definition | An individuals' observable traits |
| Allele definition | An alternate form of a gene |
| Allele dominance definition and example | One allele dictates the phenotype --> capital letter; T |
| Recessive Alleles definition and example | Alleles hidden by dominant alleles --> lower case; t |
| Genotype definition and example | An individuals' allele combination, example: TtQq |
| Homozygous Dominant definition and example | Both alleles are dominant, example: TT |
| Homozygous Recessive definition and example | Both alleles are recessive, example: tt |
| Heterozygous definition and example | A pair of nonidentical alleles, example: Tt |
| Who was Gregor Mendel? | Scientist who founded the field of genetics through breeding experiments with garden peas |
| Genetic Cross definition | Sexually combining gametes |
| Monohybrid Cross definition and generation names | Genetic cross involving one trait, generations --> P: Parental generation, F1: Offspring of parental generation (familial), F2: Offspring of F1 generation, has a 6 step process |
| 6 Steps of Genetic Crossing and examples in each | Pick trait, define alleles (Q or q), define phenotypes and genotypes of diploid P generation (Dominant = purple, recessive = yellow), define possible gametes, (Q or q), Set up a cross; fill it in, identify possible genotypes of offspring (QQ, Qq, or qq) |
| Genotype Ratio of Qq and Qq cross | 1:2:1 (QQ, Qq, Qq, qq) |
| Phenotype Ratio of Qq and Qq cross | 3 (purple seeds): 1 (yellow seeds) |
| Test Cross definition | A cross between individuals with a dominant phenotype and recessive phenotype to figure out the genotype of the one with the dominant phenotype |
| Test Cross example | Punnett square of FF and ff as well as Ff and ff (If offspring do not show ff trait, then you can determine that the dominant genotype is FF or vice versa) (Pink vs blue feathers) |
| Beyond Mendelian Inheritance (3 Explanations) | Living organisms are complex, inheritance of many traits can vary from original Mendelian genetics, principles established by Mendel can still help us understand these more complex situations |
| Incomplete Dominance definition | Heterozygote phenotype is intermediate to either homozygote, no need for test cross |
| Incomplete Dominance example | Homozygous R1 = Red, Homozygous R2 = white, and Heterozygote = pink (intermediate) --> R1R1 (Red), R2R2 (white), and R1R2 (pink) |
| Incomplete Dominance human example | FH, which causes fatty deposits in skin and tendons, homozygotes for mutant allele: May have heart attacks during childhood, Heterozygotes: May suffer heart attacks during early adulthood, Homozygotes for normal allele: Do not have disorder |
| Polyallelic Traits definition | Some traits controlled by multiple alleles, gene exists in >2 allelic forms, each individual only has two alleles |
| Polyallelic Traits example | Example: AaAa, organism can get Aa, aa, Aa, or aa |
| Polyalleic Traits human example | ABO blood types, IA = A antigen on red blood cells, anti-B antibody in plasma, IB = B antigen on red blood cells, anti-A antibody in plasma, i = Neither A nor B antigens on red blood cells, both anti-A and anti-B antibodies in plasma |
| Codominance definition | More than one allele is fully expressed |
| Codominance human example | ABO blood types, both IA and IB are expressed in the presence of the other, IAIA or IAi = Type A, IBIB or IBi = Type B, IAIB = Type AB, ii = Type O |
| Antibody definition | Protein component of the immune system that circulates and recognizes foreign substance |
| Polygenetic definition | Trait is controlled by two or more genes, each dominant allele adds to the intensity of phenotype, more continuous phenotypes, can also be influenced by the environment |
| Polygenetic human examples | Eye color, height, skin color, aabbcc (short) and AABBCC (tall) --> AaBbCc (medium) or AaBbCc (medium) and AaBbCc (medium) --> Many height variations |
| Sex-Linked inheritance definition | Genes on the sex chromosomes, sex-linked generally = X-linked, in mammals genetic females = XX & genetic males = XY, X-linked traits have nothing to do with gender --> carried on the X chromosome but not Y, more likely to be found in genetic males (1 X) |
| Sex-Linked inheritance example | X (normal gene), x (abnormal recessive gene), y (normal producing male offspring), Parents: XX and xY, Offspring: Xx, XY, Xx, XY --> Parents: Xx and XY, Offspring: XX, XY, xX, xY |
| Three X-Linked Disorders in Humans | Color blindness, muscular dystrophy, and hemophilia |
| Color Blindness definition | Alleles for red and green sensitive pigments --> on X |
| Musculur Distrophy definition | Wasting of muscle, caused by absence of muscle protein |
| Hemophilia definition | Absence or minimal presence of certain clotting factor, blood either does not clot or clots very slowly |
| Genetic material of DNA | Genes (genotype) lead to proteins (phenotype), DNA is made of nucleotides |
| Four Nitrogenous Bases of DNA | Pyrimidines (one ring) -->Thymine (T) and Cytosine (C), Purines (two rings) -->Adenine (A) and Guanine (G) |
| How a molecule with only 4 different nucleotides can produce the great diversity of life on Earth | Size: Having many nucleotides (bases) allows for great variability, Each human chromosome: 140 million base pairs, At each position: 1 of 4 (A,C,T, or G), Total # of possible sequences --> 4:2^140,000,000 |
| How nucleotides connect together to form genetic material | Phosphates between nucleotides bond together (Sugar phosphate backbone), DNA has directionality, DNA strands runs antiparallel, DNA has complementary base pairing: G --> C (3 H-bonds), A --> T (2 H-bonds) |
| Example of complementary base pairing | Example: 5'ATCCCGTATACGC3' --> complementary DNA code is --> 3'TAGGGCATATGCG5' |
| DNA replication makes an ___? | Exact copy of all chromosomes |
| Semiconservative Replication definition | Each strand of original DNA is a template for a new strand, each new DNA molecule has one old strand and one new strand |
| Three Steps in DNA Replication | Unwinding and separation of the two DNA strands, add new nucleotides to the template strands, and joining nucleotides together to build new strand |
| Key Enzyme in the first step of DNA replication | DNA Helicase: Unwinds DNA; separates 2 strands so they can be templates |
| Two Key Enzymes in the second step of DNA replication | DNA Primase: Attaches small piece of RNA (primer) to mark where to start replication, DNA Polymerase: Adds nucleotides to 3' end of new strand --> proofreads: finds and corrects errors |
| Key Enzyme in the third step of DNA replication | DNA Ligase: Acts as "glue" to connect DNA fragments in the lagging strands |
| How Replication looks in the DNA in Eukaryotes | Linear chromosomes, replication starts at many points, replication bubbles spread until they meet |
| How Replication looks in the DNA of Prokaryotes | Chromosome = Large circular loop of DNA, replication starts at origin of replication (just one), produces two identical circles |
| The "Central Dogma" of Biology | DNA (deoxyribonucleic acid) -(transcription)-> RNA (ribonucleic acid) -(translation)-> protein |
| Gene Expression definition and steps | Flow of information from DNA, to RNA, to an expressed protein, transcription and translation |
| Transcription definition | First step of gene expression, DNA 'copied' into RNA, one strand of DNA is the template for RNA, RNA made complimentary to gene |
| Translation definition | Second step of gene expression, RNA is read by ribosomes and turned into a protein, occurs in the cytoplasm, mRNA is read in codons |
| DNA nitrogenous bases, # of strands, sugar, and location in eukaryotic cell | A, C, T, G, 2, deoxyribose, and nucleus |
| RNA nitrogenous bases, # of strands, sugar, and location in eukaryotic cell | A, C, U, G, 1, ribose, nucleus and cytoplasm |
| Transcription enzyme and process | RNA Polymerase: Enzyme that binds to a promoter sequence, indicates where the gene starts, pull DNA strands apart, add nucleotides to make a strand of RNA (aka transcription), stop when it reaches a termination sequence |
| Transcription example | 5'TTAGGTCATC3' --> 3'AAUCCAGUAG5' (mRNA) |
| mRNA Modification definition | mRNA (messenger RNA) leaves the nucleus to be translated , vulnerable to being broken down when outside nucleus, must be modified before leaving nucleus |
| Three steps of mRNA Modification | 5' cap, Poly-A tail added to 3' end, Remove information that doesn't code for a protein |
| 5' cap explanation | First step to mRNA Modification, helps mRNA find the ribosome |
| Poly-A tail added to 3' explanation | Second step to mRNA Modification, 150-200 adenines (A), slow down damage from enzymes, Example: CGUUACGAUUAAAAAAAAAAA... |
| Remove information that doesn't code for a protein explanation | Third step to mRNA Modification, Exon: Code for proteins, Introns: Non-coding regions, Introns are removed (spliced) and exons sewn together to form mature mRNA |
| mRNA Modification example | 5'UAGCCCGUGC3' --> 5'TAGCCCGTGC3' (coding strand of DNA for mRNA) |
| Codon definition and examples | Groups of three nucleotides, examples: AAA, CGU, each codon codes for one amino acid, 64 possible codons (~20 amino acids), each amino acid can have several codons that code for it |
| Codon Chart definition (don't need to memorize example) | Identifies the amino acid associated with each codon on mRNA , read based on order of three nucleotides in the codon, example: Codon --> ACG ---> Amino Acid --> Threonine (Know how to read chart/find name of amino acids) |
| Three main types of RNA | Messenger RNA (mRNA), Transfer RNA (tRNA), and Ribosomal RNA (rRNA) |
| Transfer RNA (tRNA) definition and example | Brings amino acid to ribosome, binds mRNA codon --> with complimentary anti-codon, example: GAA is the anti-codon to CUU |
| Ribosomal RNA (rRNA) definition | Ribosomes, made of rRNA and protein, large and small subunits, 3 parts to process |
| Initiation definition | First step to make mRNA, Small subunit of ribosome attaches to mRNA, mRNA moves along small subunit until start codon is found (AUG), AUG codes for amino acid Met., large subunit binds with small subunit to start making chain |
| Elongation definition | Second step to make mRNA, TRNAs bring amino acids to ribosome, match anti-codons on tRNA with codons on mRNA, new amino acids get attached to previous amino acids to build a polypeptide chain |
| Termination definition | Third step to make mRNA, Ribosome reads a stop codon -->UAA, UAG, and UGA, code for a release factor that signals the end of the process, --> ribosome subunits separate, mRNA is released |
| Gene Regulation definition | Process of turning genes on and off |
| Operon definition | Group of structural and regulating genes that function as a single unit |
| Regulating Gene definition | Controls the expression of another gene of genes; does not code for a protein |
| Promoter definition | Short sequence of DNA where RNA Polymerase attaches and starts transcribing |
| Structural Gene definition | Codes for the amino acid sequence of a protein |
| Operator definition | Short DNA sequence before structural gene that can act as a control |
| Operon Model in Gene Regulation Role | 1 mRNA making several proteins that are part of the same metabolic pathway, making all the proteins (enzymes) for a metabolic pathway are controlled together |
| Two Differences between Eukaryotes & Prokaryotes | Eukaryotes can be multicellular with cell specialization, Eukaryotes have a nucleus/Prokaryotes don't |
| Five Controls on Eukaryote Gene Expression | Chromatin structure, transcriptional control, posttranscriptional control, translational control, and posttranslational control |
| What is Chromatin Structure? | Chromatin packing is used to turn genes off |
| Chromatin definition | DNA plus proteins; can condense into a chromosome |
| Barr Body definition and example | Chromatin is packed so tight that no genes on the chromosome are expressed, example: X chromosomes |
| What is Transcriptional Control? | Control which genes are transcribed, depends on environment and development of the organism, transcription won't start without multiple helper proteins (transcription factors and activators) |
| Transcription Factors Role | Help RNA polymerase bind to promoter in transcriptional control |
| Activator Role | Bind to enhancer sequences and need to interact with promoter in transcriptional control |
| What is Posttranscriptional Control and what is a human example? | Different splicing of exons (keep) and introns (cut out), slightly different proteins, different gene expression, human Example: protein hormone calcitonin is made in hypothalamus and thyroid gland |
| What is Translational Control? | 5' cap --> if left off, mRNA can't find a ribosome, no gene expression, Poly-A tail (Long lived mRNA when it has long tail/short lived mRNA when it has short tail) |
| What is Posttranslational Control? | Active proteins, proteins don't last forever, unneeded proteins get tagged and transported to lysosomes |
| Gene Mutation definition and example | A permanent change in the sequence of bases in DNA, Examples: ATTCCG changing to ATTTCG, ATTCCG changed to ATTCG, range of effect: no effect -->-->-->-->--> complete inactivity |
| Where Germline Mutations occur and who it does/doesn't affect | Occurs in sex cells, passed on to next generation |
| Where Stomatic Mutations occur and who it does/doesn't affect | Occur in body cells, impact a small area, not passed on to future generations |
| Spontaneous Mutations (Cause of Gene Mutations) and an example | No apparent reason, some sort of abnormality during a biological process, Example: Mispairing of nucleotides during DNA replication |
| Induced Mutations (Cause of Gene Mutations) and an example | Result from environmental exposure, Example: Toxic chemical, caused by mutagen |
| Mutagen definition | Environmental factor that changes DNA, some mutagens are carcinogens: cancer-causing |
| Example of Induced Mutations in humans | Sickle-shaped red blood cells --> One base substitution in the hemoglobin gene, changes one amino acid (a glutamic acid is now a valine), completely alters shape of red blood cell |
| Genomics definition | Area of study that examines the genome of a species or group of species |
| Genome definition | All the genetic information of an individual (or species) |
| What was the Human Genome Project? | Started in 1990, 13-year project from labs around the globe, 20,500 genes |
| Coding Sequences definition | Genomes that code for proteins (exon) |
| Non-Coding Sequences definition | Genomes, or introns, regulatory sequences, repetitive DNA (2 or more nucleotides repeat --> CTCTCTCT...), unknown |
| Functional Genomics definition | Understand the exact role of the genome, gene functions and interactions |
| Comparative Genomics definition | Compares human genome to other organisms, model organisms with common genetic mechanisms and cellular pathways, used to study evolution, medical conditions, and more |
| Biotechnology definition | Using DNA technology and genetic engineering to alter an organism to benefit an ecosystem or human activity |
| DNA Sequencing definition and how it is accomplished | Type of DNA techonology used to determine the order of nucleotides in a piece of DNA, How --> One method attaches a dye to each type of nucleotide, use laser to automatically read dyes |
| Recombinant DNA (rDNA) definition | Type of DNA technology that contains DNA from two or more different sources |
| Bioinformatics is the application of combining what three things? In what three areas of study is it important? | Computer technology, statistics, really big biological data sets (genome databases), important in medicine, ecology, and evolution |
| Genetic Engineering definition | Modifying the genome of an organism |
| GMO (Genetically Modified Organisms) definition | An organism that has been genetically engineered to contain a gene from another species |
| Four ways GMOs are beneficial | GMOs can improve human health: Human Insulin made in bacteria, GMOs can help the environment: Plastic and oil-eating bacteria, GMOs in plants: Agricultural crops --> resistance to insects (Ex: Bt Corn), GMOs in humans and medicine: Gene therapy |
| Gene Therapy definition and how it could help | Give patients healthy genes to make up for faulty genes, virus often used to transport gene, in the US gene therapy is in clinical trials, could help with a variety of diseases (Cancer, AIDS, cystic fibrosis, heart disease, diabetes, etc.) |
| Gene Editing definition and example | Targeting a specific sequence of DNA for removal or replacement, Example: CRISPR |
| Three Ethical Issues related to Gene Therapy | How can "good" and "bad" uses of gene therapy be distinguished? Who decides which traits are normal and which constitute a disability or disorder? Will the high costs of gene therapy make it available only to the wealthy? |
| Two more Ethical Issues related to Gene Therapy (Society) | Could the widespread use of gene therapy make society less accepting of people who are different? Should people be allowed to use gene therapy to enhance basic human traits such as height, intelligence, or athletic ability? |
Created by:
AnaHuls