Chapter 4: Genetics and Cellular Function Flashcards
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| 7350505137 | DNA | -deoxyribonucleic acid -long, threadlike molecule with a uniform diameter but varied length -46 DNA molecules in the average nucleus -DNA and other nucleic acids are polymers of nucleotides |  | 0 |
| 7482638082 | Law of complementary base pairing | One strand determines base sequence of other | 1 | |
| 7482728182 | Discovery of Double Helix | 1900:components of DNA(sugar,phosphate base) known 1953: X ray determined geometry of DNA Nobel prize 1962 to Watson, Crick, Wilkins Rosalind Franklin: discover DNA shape didn't get credit due to her gender | 2 | |
| 7350505138 | nucleotide | consists of one sugar (deoxyribose), one phosphate group, one nitrogenous base -either a pyrimidine (single carbon-nitrogen ring) -or a purine (double ring) |  | 3 |
| 7350505139 | purines | double ring -adenine (A) -guanine (G) |  | 4 |
| 7350505140 | pyrimidines | single ring -cytosine (C) -thymine (T) -uracil (U) |  | 5 |
| 7350505141 | DNA strucutre | -molecular shape is a double helix (spiral staircase) -sidepiece- backbone composed of phosphate groups alternating with sugar -"steps" are nitrogenous bases |  | 6 |
| 7350505142 | nitrogenous bases | held together by hydrogen bonds -purine on one backbone and pyrimidine on the other - A-T two hydrogen bonds - G-C three hydrogen bonds (stronger) | 7 | |
| 7350505143 | genes | genetic instructions for synthesis of proteins |  | 8 |
| 7350505144 | gene | an information-containing segment of DNA that codes for the production of a molecule of RNA that plays a role in synthesizing one or more proteins | 9 | |
| 7350505145 | genome | Total set of genes in 23 pairs of chromosomes. Approx 30K genes(2%DNA) Noncoding DNA (98% of DNA) | 10 | |
| 7350505146 | chromatin | fine filamentous DNA material complexed with proteins - occurs as 46 long filaments called chromosomes |  | 11 |
| 7350505147 | histones | disc-shaped cluster of eight proteins -DNA molecule winds around cluster -appears to be divided into repeating segments called nucleosomes |  | 12 |
| 7350505148 | nucleosome | consist of core particle (histones with DNA around them) and linker DNA (short segment of DNA connecting core particles) | 13 | |
| 7350505149 | chomatin | Fine filamentous DNA material complexed with proteins | 14 | |
| 7350505150 | Chromosomes | 46 comes in pairs of 23 One from each parent Each pair same gene but diff version (alleles) | 15 | |
| 7350505152 | RNA | smaller cousin of DNA (fewer bases) -mRNA, rRNA, tRNA -one nucleotide chain -sugar is ribose -uracil rather than thymine -function: interpret code in DNA, uses the instructions for protein synthesis, leaves nucleus and functions in cytoplasm | 16 | |
| 7350505153 | human genome project | identified the nitrogenous base sequences of 99% of the human genome | 17 | |
| 7350505154 | geonomics | study of the whole genome and how its genes and non-coding DNA interact to affect the structure and function of the whole organism | 18 | |
| 7350505155 | genetic code | a system that enables these four nucleotides to code for the amino acid sequence of all proteins | 19 | |
| 7350505156 | base triplet | a sequence of three DNA nucleotides that stands for one amino acid | 20 | |
| 7350505157 | codon | the 3-base sequence in mRNA | 21 | |
| 7350505158 | how many possible codons are available to represent the 20 amino acids? | there are 64 possible codons to represent the 20 amino acids but only 61 code for amino acids | 22 | |
| 7350505159 | start codon | AUG | 23 | |
| 7350505160 | stop codons | UAG, UGA, UAA | 24 | |
| 7350505161 | mRNA (messenger RNA) | a RNA mirror image of the gene is made by the process of transcription | 25 | |
| 7350505162 | ribosomes (rRNA) | cytoplasmic granules composed of ribosomal RNA and enzymes | 26 | |
| 7350505163 | tRNA (transfer RNA) | delivers amino acids to the ribosome | 27 | |
| 7350505164 | process of protein synthesis: | DNA --> mRNA --> protein | 28 | |
| 7350505165 | transcription | -step from DNA to mRNA -occurs in nucleus where DNA is located -where it finds A it adds U. where it finds T it adds A, where it finds C it adds G, and where it finds G it adds C | 29 | |
| 7350505166 | RNA polymerase | enzyme that binds to the DNA and assembles mRNA | 30 | |
| 7350505167 | translation overview | -step from mRNA to protein -RNA polymerase rewinds the DNA helix behind it 15-20% proteins synthesized in the nucleus | 31 | |
| 7350505168 | terminator | base sequence at the end of a gene which signals polymerase to stop | 32 | |
| 7350505169 | pre-mRNA | immature RNa produced by transcription | 33 | |
| 7350505170 | exons | "sense" portions of the immature RNA -will be translated to protein | 34 | |
| 7350505171 | introns | "nonsense" portions of the immature RNA -must be removed by translation | 35 | |
| 7350505172 | alternative splicing | removing the introns by enzymes and splicing the exons together into a functional RNA molecule -one gene can code for more than one protein | 36 | |
| 7350505173 | translation process | 3 steps: initiation, elongation, termination | 37 | |
| 7350505174 | intitiation | -leader sequence mRNA binds to small ribosomal subunit -initiator tRNA pairs with start codon -large ribosomal subunit joins the complex and the now fully formed ribosome begins reading bases | 38 | |
| 7350505175 | elongation | -next tRNA binds to ribosome while its anticodon pairs with next codon of mRNA -peptide bond forms between start codon and second amino acid -ribosome slides to read next codon and releases next initiator tRNA -next tRNA with appropriate anticodon brings its amino acid to ribosome -another peptide bond forms -process repeats | 39 | |
| 7350505176 | termination | -when ribosome reaches stop codon a release factor binds to it -finished protein breaks away from ribosome -ribosome dissociates into two subunits | 40 | |
| 7350505177 | polyribosome | one mRNA holding multiple ribosomes | 41 | |
| 7350505178 | protein synthesis is not complete until ____. | it coils or folds into precise secondary and tertiary structure and may require post-translational modificatio | 42 | |
| 7350505179 | DNA helicase | an enzyme, opens one short segment of helix at a time ezposing its nitrogenous bases | 43 | |
| 7350505180 | replication fork | point where the DNA is opened up (like two separated halves of a zipper) | 44 | |
| 7350505181 | DNA polymerase | molecules move along each strand, read exposed bases, match the complementary free nucleotides, two separated strands of DNA are copied by separate polymerase molecules proceeding in opposite directions | 45 | |
| 7350505182 | mutations | changes in DNA structure due to replication errors or environmental factors | 46 | |
| 7350505183 | cell cycle | extends from one division to the next | 47 | |
| 7350505184 | interphase includes | G1 phase S phase G2 phase | 48 | |
| 7350505185 | G1 phase | -first gap phase -interval between cell birth from division and DNA replication -carries our normal tasks and accumulates materials needed to replicate DNA | 49 | |
| 7350505186 | S phase | synthesis phase where DNA replication occurs | 50 | |
| 7350505187 | G2 phase | -second gap phase -interval between DNA replication and cell division -synthesizes enzymes that control cell division -repairs DNA replication errors | 51 | |
| 7350505188 | M phase | -miotic phase -cell replicates its nucleus in 4 phases -pinches in two to form new daughter cells (cytokinesis) | 52 | |
| 7350505189 | G0 phase | cells that have left cycle for a "rest" temporarily or permanently | 53 | |
| 7350505190 | mitosis | cell division in all body cells except the eggs and sperm; results in 2 genetically identical daughter cells | 54 | |
| 7350505191 | four phases of mitosis | prophase, metaphase, anaphase, telophase | 55 | |
| 7350505192 | prophase | chromosomes shorten and thicken, coiling into two compact rods |  | 56 |
| 7350505193 | metaphase | chromosomes are aligned on cell equator |  | 57 |
| 7350505194 | anaphase | activation of enzyme that leaves two sister chromatids apart at centromere |  | 58 |
| 7350505195 | telophase | chromatids cluster on each side of the cell |  | 59 |
| 7350505196 | when do cells divide? | -have enough cytoplasm for two daughter cells -have replicated their DNA -have adequate supply of nutrients -stimulated by growth factors -neighboring cells die, opening up space in a tissue to be occupied by new cells | 60 | |
| 7350505197 | when do cells stop dividing? | -snugly contact neighboring cells -nutrients or growth factors are withdrawn -undergo contact inhibition- cessation of cell division in response to contact with other cells | 61 | |
| 7350505198 | heredity | transmission of genetic characteristics from parent to offspring | 62 | |
| 7350505199 | karyotype | chart of 46 chromosomes laid out in order by size and other physical characteristics |  | 63 |
| 7350505200 | homologous chromosomes | the two members of each pair (23 pairs) |  | 64 |
| 7350505201 | diploid | any cell with 23 pairs of chromosomes (somatic cells) | 65 | |
| 7350505202 | haploid | contain half as many chromosomes as somatic cells: sperm and egg cells (germ cells) | 66 | |
| 7350505203 | fertilization | restores diploid number to the fertilized egg and the somatic cells rise from it | 67 | |
| 7350505204 | locus | location of particular gene on a chromosome | 68 | |
| 7350505205 | alleles | different forms of a gene at same locus on two homologus chromosomes | 69 | |
| 7350505206 | dominant allele | (capital letter) -masks effect of recessive allele that may be present -produces protein responsible for visible trait | 70 | |
| 7350505207 | recessive allele | (lowercase) -expressed only when present on both of the homologous chromosomes -no dominant alleles at that locus -often codes for nonfunctional variant of the protein | 71 | |
| 7350505208 | geneotype | alleles that an individual possesses for a particular trait -homozygous -heterozygous | 72 | |
| 7350505209 | homozygous | two identical alleles for a trait | 73 | |
| 7350505210 | heterozygous | different alleles for that gene | 74 | |
| 7350505211 | phenotype | observable trait | 75 | |
| 7350505212 | gene pool | collective genetic makeup of population as a whole | 76 | |
| 7350505213 | multiple alleles | more than two allelic forms for a trait | 77 | |
| 7350505214 | codominant | both alleles are equally dominant | 78 | |
| 7350505215 | incomplete dominance | phenotype intermediate between traits each allele would have produced alone | 79 | |
| 7350505216 | polygeneic inheritance | genes at two or more loci, or even different chromosomes, contribute to a single phenotypic trait ( skin/eye color, alcoholism,mental illness,cancer,heart disease) | 80 | |
| 7350505217 | pleiotrpy | one gene produces multiple phenotypic effects | 81 | |
| 7350505218 | sex linked traits | carried on the X or Y chromosome, and therefore tend to be inherited by one gender more than the other | 82 | |
| 7482728183 | Pleitropy | One gene produces multiple phenotypic effects (sickle cell, Marian's syndrome, Alkaptonuria) | 83 | |
| 7350505219 | penetrance | percentage of a population with a given genotype that actually exhibits the predicted phenotype | 84 | |
| 7350505220 | epigenetics | field examining nongenetic changes that alter gene expression and can be passed to offspring | 85 | |
| 7350505221 | DNA methylation | mechanism or epigenetic change in which methyl groups are added to DNA | 86 | |
| 7350505222 | benign tumor | slow growth; usually easy to treat | 87 | |
| 7350505223 | malignant tumor | cance; fast growing | 88 | |
| 7350505224 | metastisize | give off cells that seed the growth of multiple tumors elsewhere (malignant tumor) | 89 | |
| 7350505225 | carcinogen | environmental cancer-causing agent- they typically mutate DNA | 90 | |
| 7350505226 | tumor angiogenesis | in-growth of blood vessels stimulated by energy-hungry tumors | 91 | |
| 7350505227 | oncogenes | cause cell division to accelerate out of control | 92 | |
| 7350505228 | tumor suppressor genes | inhibit development of cancer when functional | 93 |