exam4

Question 1

explain two examples of traits that do not follow mendel’s rules

Question 2

calculate offspring phenotypic ratios for traits that do not follow typical dominant-recessive patterns

Question 3

calculate offspring phenotypic ratios for traits determined by genes on the X chromosome

Question 4

define incomplete dominance

Answer 4

two (different trait/gene?) alleles produce a blended phenotype

Question 4

explain the process of sex linkage + the significance/impact/importance

Answer 4

sex chromosomes pair during prophase 1; then segregate during anaphase 1 and the process of meiosis (sex cells and gametes)

Question 4

define hemizygous and the impact it has on the presentation/effect of X- and Y-chromosome traits

Answer 4

the condition where an individual has only one copy of a gene or chromosome segment, rather than the usual two (XY vs. XX)
can lead to increased vulnerability to X-linked genetic disorders and a more pronounced expression of genes

Question 5

where is the sex-determining region Y on a chromosome; define the SRY gene

Answer 5

in the upper right short arm (towards the top of the short arm)

Question 6

what are primary and secondary pseudoautosomal regions and where are they located on the chromosome

Answer 6

pseudoautosomal regions (aka PARs) are homologous sequences of nucleotides found within the sex chromosomes of species with an XY [1] or ZW [2] mechanism of sex determination; located on the caps of each chromosome end portion

Question 7

compare DNA to a language: what are the letters, words, and sentences; in what direction does a cell read

Answer 7

letters- A, T, G, C
words- codons
sentences- strings of codons (start codon = capital letter; stop = period/punctuation)
direction read- 5’ to 3’ on the coding strand and mRNA

Question 8

what are the two identities of DNA

Answer 8

one- macromolecule that participates in chemical reactions
two- language containing coded instructions for building proteins

Question 8

genes are the region on DNA that codes for proteins: T/F

Answer 8

true

Question 9

define central dogma and how + why the process occurs

Answer 9

the flow of info from DNA to mRNA to proteins

process: genes in DNA are transcribed to make mRNA (messenger RNA) to then be carried by the mRNA from the nucleus to the cytoplasm, for the purpose of being translated into proteins to expressed genetic coding (genes and traits)

Question 10

describe the process of transcription vs. translation

Answer 10

copying info in DNA: genes from within the DNA is transcribed to make mRNA vs. converting info from RNA language to amino acid/protein language (what? language?)

Question 11

draw out the process of transcription and translation (include template strand, coding strand, mRNA, codon, amino acids, protein/polypeptide bonds)

Answer 11

*mRNA should be an exact copy of the coding stand (except with U[racil] opposed to T[hymine]) and complementary to the template stand
*codons = specific amino acids

Question 12

define codon- which ones important for start, stop, etc?

Answer 12

a section of three nucleotides, equal to specific amino acids

Question 13

coding strand vs. template strand how do you know which is which

Answer 13

coding = 5’ to 3’
template = 3’ to 5’

Question 14

what materials are required and used during the process of transcription; how does the transcriptional machinery know where to start or stop transcribing the DNA?

Answer 14

done by RNA polymerase II (ribonucleotide triphosphates; why is it called two?), transcription factors (proteins that interact with DNA and influence transcription), nucleotide triphosphates (NTPs), DNA template

specific codons?

Question 15

what is the purpose of transcription, where and when is it done

Answer 15

transcription is for the purpose of making a portable, transient copy of info in the DNA; located in the nucleus (specifically euks?); when needing to make the stuff/proteins encoded by a gene; how _?

Question 16

what are the phases of transcription and what happens during them (reference notebook)

Answer 16

one- initiation (happens in euks [eukaryotic cells]) the TATA box signals to transcriptional machinery that a gene is about to start, transcription factors (proteins that interact w/ specific DNA sequences) and RNA polymerase II begin the process of the RNA transcript

two- elongation (happens in euks and proks) the RNA polymerase II creates/connects RNA nucleotides anti-parallel and complementary to the coding strand

three- termination (happens in euks) the RNA polymerase II moves past the end of the informational part of the gene and eventually “falls off” the DNA as several RNA-modifying enzymes interact w/ the new RNA; after some processing the RNA will be ready to be translated

Question 17

explain why it is more likely for an XY individual to be color blind than an XX individual

Answer 17

color blindness is a recessive X-linked trait; meaning an XY individual would need just one color-blind X allele from their XX parent (since the other passes down the Y chromosome) vs. an XX individual would need both parents to have at least one color-blind X allele and for both to be passed down

Question 18

describe how the cell prepares a newly transcribed RNA for translation; what modifications are made to the ends, what modifications are made to the middle, and why are these modifications necessary for translation

Answer 18

from 12/2 - will also be in annotations of 12/4 slides