Genetics Exam 3

what is the coefficient of relationship between Ike and Flame?

0.31

given the template strand of DNA, 3' - GCTAAGGTCGAC - 5', what would be the nucleotide sequence of the RNA transcript obtained from the template strand?

5' - CGAUUCCAGCUG -3'

termination of polypeptide chain occurs when any of the three stop codons enter the A site of a ribosome, which codon will result in termination of polypeptide chain?

UAA

__ is a group of alleles in an organism that are inherited together form a single parent

a haplotype

transfer RNA molecules contain nucleotide triplets that will pair with the codons in the mRNA transcript during translation. those nucleotide triplets in the tRNA are called:

anticodon

__ is an increase in performance of outbred offspring over parental average of purebred lines

heterosis

what is true about RNA molecules

messenger RNA molecules carry genetic information from DNA to ribosomes where proteins are synthesized; transfer RNA molecules function as adaptors between amino acids and the codons in mRNA during translation; ribosomal RNA molecules are structural and catalytic components of the ribosomes; microRNA molcules modulate gene expression

all but two of the 20 amino acids are specified by more than one codon. what two amino acids are specified by just one codon?

methionine and tryptophan

how many nucleotides does each codon contain?

three

the transfer of genetic information from RNA to protein is known as:

translation

true or false: codons for AA with similar chemical properties are closely related, usually differing by a single nucleotide

true

true or false: during the process of protein synthesis, each amino acid is specified by one or more codons

true

true or false: polypeptides are composed of amino acids

true

true or false: proteins exist in three dimensional space. the primary structure pf proteins refers to the amino acid sequence forming the polypeptides

true

true or false: ribosomes are composed of about 50% protein and 50% RNA

true

true or false: the genetic code contains specific codons used to initiate and to terminate polypeptide chains

true

what is correct about the degenerate and ordered property of genetic code?

AA with similar chemical properties have codons that differ by only one base; single base pair mutation may only result in the substitution of one AA for another AA with similar properties; minimizes the effects of mutation

given a DNA template strand 5' GACCTG 3', what amino acids are specified by the mRNA codons transcribed from this template DNA?

Gln and Val

the mechanism of RNA system synthesis is similar to that of DNA synthesis. however, RNA synthesis is different in that:

RNA chains can be synthesized from the scratch; and only one strand of DNA is used as a template to synthesize a complementary RNA transcript

what is correct about RNA chain elongation during transcription?

RNA polymerase unwinds the DNA ahead of it and rewinds the DNA behind it; RNA polymerase adds nucleotides that are complementary to the template strand of DNA; nucleotides are added to the growing chain of RNA molecule, one nucleotide at a time

the degeneracy property of the genetic code refers to the fact that:

all amino acids, except methionine and tryptophan are specified by more than one codon

what is among the main parts of amino acids?

amino group, carboxyl group, and varying side chain

what is correct about the tRNA binding sites on each ribosome?

aminoacyl site binds incoming tRNA which is carrying the next amino acid to be added to the growing polypeptide chain; peptidyl site binds tRNA attached to the growing polypeptide; exit site binds the departing tRNA, which is "uncharged" as it no longer has amino acid attached

wobble hypothesis refers to the fact that:

base substitution in the third position of many codons does not change amino acid specified by the codon

what is among the three steps of polypeptide chain elongation?

binding of a tRNA to the aminoacyl site of the ribosome; growing polypeptide chains from the tRNA in the peptidyl site transferred to tRNA in the aminoacyl site by the formation of a new peptide bond; translocation of the ribosome along the mRNA to position the next codon in the aminoacyl site

what is correct about initiation of translation?

cap binding protein binds to 5' 7-methyl guanosine cap; initiation complex scans the mRNA and finds the start codon (AUG); initiation tRNA(Met) enters directly into the P site of the ribosome

the central dogma of genetics refers to the fact that -

genetic information is stroed in DNA and is transferred from DNA to RNA; mRNA is converted to proteins

the subdiscipline of genetics that focuses on the structure and function of entire genomes

genomics

the term __ refers to copies of the same ancestral allele

identical by descent

__ increases the frequency of homozygous recessive alleles

inbreeding

__ __ is defined as the probability that both alleles at any given locus in the animal's genotype are identical by descent

inbreeding coefficient

what is the impact of inbreeding on phenotype?

increased uniformity in offspring of inbred parent; increased prevalence of genetic disorders; decreased average performance of inbred offspring

what is true about the genetic code?

is composed of nucleotide triplets; three nucleotides in mRNA specify one AA; each nucleotide in mRNA belongs to just one codon; is "comma-free" i.e. codons are read consecutively

what is true about the inherited genetic disorder known as phenylketonuria (PKU)?

loss of function of phenlyalanine hydroxylase results in the disorder; if undiagnosed, PKU results in mild to severe brain damage; only individuals that are homozygous recessive for the mutated phenylalanine hydroxylase gene (PAH) will be affected by the disorder; phenylalanine builds up in the body as it cannot be converted to tyrosine

what RNA molecule is translated to protein?

mRNA

what is correct about the genetic link to alzheimer's disease?

missense mutation in the presenilin 1 gene (PSEN1) changes the synthesis of amino acid (glutamic acid to alanine); protein synthesized from the mutated gene does not cleave peptides correctly

what factors affect allele and genotype frequencies?

mutation, migration, selection, and random chance via segregation and independent assortment

where on the mRNA transcript does the initiation complex form?

not sure

transcription is the first step of gene expression and it occurs in the __

nucleus

__ increases the frequency of heterozygotes in a population

outbreeding

a compound composed of 2 or more amino acids is known as:

peptide

amino acids in polypeptides are covalently bonded with each other. the bond formed between an amino group of one amino acid and the carboxyl group of a second amino acid is known as:

peptide bonds

during termination of the polypeptide chain, what is true?

release factor recognizes the stop codon, enters the A site, and releases the polypeptide from the tRNA molecule in the P site; mRNA molecule released from the ribosome; the ribosome subunits dissociate from the RNA

what is required for protein synthesis?

ribosomes; transfer RNAs; messenger RNA; amino acids

what is not correct about reading frame?

single base pair addition or deletion will not alter the amino acid sequence after the mutation

what RNA molecules are structural components of spliceosomes?

small nuclear RNAs (snRNAs)

in eukaryotes, pre-mRNAs should go through a process called splicing, during which introns are removed by splicing reactions carried out by:

spliceosomes

what are exons?

the coding sequences of a gene (expressed sequences that are translated)

the transfer of genetic information from DNA to RNA is known as:

transcription

in order to initiate RNA synthesis, RNA polymerases require assistance from proteins known as __ __

transcription factors