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IS II
Ms. Akers Final Exam
| Term | Definition |
|---|---|
| Nucleic Acids (DNA & RNA) | Rounded structures located in the cytoplasm |
| Chromosome | a cell structure that carries genetic material |
| Centromere | cell structure that joins two sister chromatids of a chromosome |
| DNA Replication | the process that occurs when DNA makes an exact copy of itself before cell division |
| Mitosis | period of nuclear cell division in which two daughter cells are formed, each containing a complete set of chromosomes |
| Tissue | groups of cells that work together to perform a specific function |
| Organ system | multiple organs that work together to perform a specific function |
| Prokaryote | an unicellular organism, such as bacteria, composed of cells that lack internal membrane-bound structures |
| Asexual reproduction | type of reproduction where one parent produces one or more identical offspring without the fusing of gametes |
| meiosis | type of cell division where one body cell produces four gametes, each containing half the number of chromosomes as a parent's body cell |
| gametes | sex cells |
| gene | a segment of DNA on a chromosome that controls a particular trait |
| Incomplete Dominance | the first-generation offspring will have a phenotype in between that of the parents |
| Haploid | a cell with one of each kind of chromosomes |
| Diploid | a cell with two of each kind of chromosomes |
| Sexual Reproduction | a pattern of reproduction that involves the production and subsequent fusion of haploid sex cells |
| allele | a trait |
| Homozygous | when there are two identical alleles for a trait |
| Heterozygous | when there are two different alleles for a trait |
| genotype | the genetic characteristics of an organism |
| Mutation | a change in the DNA sequence, chromosomal-parts of chromosomes are broken off and lost during mitosis and meiosis |
| tRNA (transfer RNA) | a small RNA molecule that can pick up amino acids. By matching its anticodon to the mRNA codon, the amino acid is put into the protein chain correctly |
| Translation | the process of making proteins using the instructions of messenger RNA molecules |
| codon | A code word of messenger RNA that represents an amino acid |
| Enzyme | a protein that controls the rate of chemical reactions in cells |
| recombinant DNA | A form of DNA produced by combining genetic material from two or more different sources by means of genetic engineering |
| cell plate | in plants, a plate that develops at the midpoint between the two groups of chromosomes in a dividing cell and that is involved in forming the wall between the two new daughter cells |
| polypeptide chain | amino acids joined together to make proteins |
| fertilization | fusion of male and female gametes |
| Polygenic inheritance | a trait, such as skin color, that is affected by the combination of several different genes |
| sex-linked trait | an inherited characteristic located on chromosomes 23 in humans |
| cell division | the multiplication of cell through processes such as mitosis |
| cytokinesis | division of the cytoplasm |
| dihybrid cross | fertilization between two organisms to study two different traits |
| monohybrid cross | fertilization between two organisms to study one trait |
| organ | group of two or more tissues organized to perform complex activities within an organism |
| centriole | in animal cells, a pair of small cylindrical structures composed of microtubules that duplicate during interphase and move to the end of the cell during prophase |
| cell cycle | continuous sequence of growh (interphase) and division (mitosis) in a cell |
| evolution | gradual change in a species through adaptations over time |
| cell theory | the theory that (1) all organisms are composed of cells, (2) the cell is the basic unit of structure & organization of organisms, and (3) all cells come from preexisting cells |
| eukaryotes | unicellular or multicellular organisms, such as yeast, plants, and animals, composed of cells containing a true nucleus and membrane-bound organelles |
| trait | characteristic that is inherited; can be dominant or recessive |
| phenotype | outward appearance of an organism, regardless of its genes |
| nondisjunction | failure of homologous chromosomes to separate properly during meiosis |
| dominant gene | a gene that prevents the expression of another gene |
| recessive gene | a gene whose expression is prevented if a dominant gene is present |
| variation | differences in expression of traits |
| protein synthesis | the process by which individual amino acids are connected to each other in a specific order dictated by the nucleotide sequence in DNA, which also involves the processes of transcription and translation |
| genetic | occurring among members of a family usually by heredity |
| inheritance | attributes acquired via biological heredity from the parents |
| sex chromosome | either of a pair of chromosomes, usually designated X & Y, that combine to determine the sex and sex-linked characteristics of an individual, with XX resulting in female and XY resulting in male |
| Natural selection | the process in nature by which, according to Darwin, only the organisms best adapted to their environment tend to survive & transmit their genetic characteristics in increasing numbers to succeeding generations while those less adapted are eliminated |
| Artificial selection | Human intervention in animal or plant reproduction to ensure that certain desirable traits are represented in successive generations |
| species | group of organisms that can interbreed and produce fertile offspring in nature |
| reproductive isolation | occurs when formerly interbreeding organisms can no longer produce fertile offspring due to an incompatibility of their genetic material or by differences in mating behavior |
| geographic isolation | occurs whenever a physical barrier divides a population, which results in individuals no longer being able to mate; can lead to the formation of a new species |
| Geological Time Scale | record of the history of life determined by the positions of layers of rock |
| gene pool | all of the alleles in a population's genes |
| Adaptation | evolution of a structure, behavior, or internal process that enables an organism to respond to stimuli and better survive in an environment |
| Fossil Records | the total number of fossils that scientists have collected which contain much information about past life on Earth, scientists know about extinct species because of this, & provides clues about how & when new groups of organisms evolved |
| gene frequency | percentage of any allele in a population's gene pool |
| Analogous structures | structures that do not have a common evolutionary origin but are similar in function |
| Homologous structures | structures with common evolutionary origins; can be similar in arrangement, in function, or both; provides evidence of evolution from a common ancestor; forlimbs of crocodiles, whales, & birds are examples |
| genetic drift | alteration of allelic frequencies in a population by chance events; results in disruption of genetic equilibrium |
| mimicry | structural adaptation evolved in some species where one species resembles another; may provide protection from predators or other advantages |
| camouflage | structural adaptation that enables a species to blend with their surroundings; allows a species to avoid detection by predators |
| punctuated equilibrium | idea that periods of speciation occur relatively quickly with long periods of genetic equilibrium in between |
| speciation | process of evolution of new species that occurs when members of similar populations no longer interbreed to produce fertile offspring |
| vestigial structure | body structure that has no function in a present-day organism but was probably useful to an ancestor; provides evidence of evolution |
| Misconceptions/Reality about Natural Selection | 1. produces perfection/does not, 2. guiding hand/result of nature making choices. 3. makes variation/does not, variation has to be there 1st because it is genetic information, 4. random/not random, mutations and reproduction are random |
| microevolution | the theory that natural selection can, over time, take an organism and transform it into a more specialized species of that organism |
| macroevolution | the hypothesis that the same processes which work in microevolution can, over a long period of time, transform an organism into a completely different kind of organism |
| Steps of Cell Divison | Mitosis-Interphase, Prophase, Metaphase, Anaphase, Telophase, Meiosis-Prophase I, Metaphase I, Anaphase I, Telophase I, Interkinesis, Prophase II, Metaphase II, Anaphase II, Telophase II |
| Significance of Mitosis | growth, cell replacement, and regeneration |
| Explain why meiosis is an essential process in a sexual reproductive cycle | meiosis is an early step in sexual reproduction in which the pairs of chromosomes spearate & segregate randomly during cell division to produce gametes containing 1 chromosome of each time |
| Contrast outcome of meiosis with that of mitosis | meiosis-not identical daughter cells, mitosis-identical daughter cells |
| Compare and contrast the structure of DNA with RNA | compare-both nuclic acids, both have four nitrogen bases; contrast-RNA single-stranded, sugar is ribose, contains uracil instead of thymine, DNA-double-stranded, sugar is deoxyribose, contains thymine |
| Explain the process of DNA Replication | 1. Hydrogen bonds open the DNA (unzip), 2. Free nucleotides attach to the open nucleotides on the DNA, 3. Two new strands |
| Explain the process of transcription | 1. DNA opens by an enzyme 2. unzips at any place along strand 3. free nucleotides attach to open DNA (1 strand only) 4. U nucleotide pairs w/ A 5. thymine only recognizes deoxyribose 6. when protein info is copied, RNA leaves nucleus & goes to ribosome |
| Explain the process of translation | 1. starting end of mRNA strand attaches to a ribosome 2. tRNA molecules, each carrying a specific amino acid, approach the ribosome 3. a tRNA anticodon pairs w/ first mRNA codon 4. pairing repeats for 2nd, 3rd, etc. 5. chain of amino acids is formed |
| Identify the result of nondisjunction | extra chrosome-Down syndrome, mising a chromosome-usually death |
| endoderm | digestive tract |
| ectoderm | skin and nervous system and brain |
| mesoderm | circulatory, skeletal, some respiratory, etc. |
| zygote | a fertilized egg |
| embryo | a developing zygote |
| stages of embryology | cleavage, morula, blastulation, gastrulation-DNA active-proteins being made-differentiation |
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sissiloo
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