Mutations and Errors
What is the difference between a silent mutation, missense mutation and nonsense mutation?
Silent: same amino acid inserted
Missense: changes amino acid inserted
Nonsense: changed to stop codon
What is the difference between phenotype and genotype?
Phenotype: physical appearance
genotype: genetic makeup
How many phases of meiosis are there?
2
What happens during elongation?
RNA extends in 5' to 3'
What is the start codon in eukaryotes?
AUG (methionine)
What is nondisjuction?
failure of c'somes to move to opposite poles during either meiotic division
Name the two different laws:
1. two alleles for a gene segregate during gamete formation (one from each parent) and are rejoined at random during fertilization
2. in a dihybrid cross, the alleles of each gene assort independently
1. law of segregation
2. law of independent assortment
Do germ line cells undergo meiosis or mitosis? Do somatic cells undergo meiosis or mitosis?
germline- meiosis
somatic- mitosis
When do transcription and translation happen in prokaryotes?
at the same time
What are the 2 functional ends of tRNA
anticodon loop, acceptor stem
What is aneuploidy? Monosomy? Trisomy?
Aneuploidy: gain or loss of a c'some
monosomy: loss
trisomy: gain
Is the parent has a genotype of : AaBBCcdd, what would the possible gametes be?
1. ABCd
2. aBCd
3. ABcd
4. aBcd
True or False:
In humans, meiosis produces four identical gametes that combine with the gametes of another individual to form a diploid zygote.
false
How does termination happen?
the end is marked by a terminating sequence, one example is a hairpin Uracil loop
How does termination occur?
A stop codon enters the A site, then a releasing factor helps release the peptide from the ribosome
What type of mutation adds or deletes bases, alters the reading frame, and has much more profound consequences?
Frameshift
what is incomplete dominance? what is codominance? Give examples of both
incomplete: the heterozygote is intermediate in phenotype between the two homozygotes (red + white = pink)
codominance: heterozygote shows some aspect of the phenotype of both homozygotes (a blood + b blood = ab blood)
Reduction division occurs due to the lack of DNA replication between which stages of meiosis?
telophase 1 and prophase 2
What happens during initiation?
sigma subunit identifies the promoter, unwinding begins at -10, 2 common 6-base sequences occur at -35 and -10
What are the 3 steps of initiation?
1. Special initiator tRNA (carries N-formylmethionine) binds to the small ribosomal subunit 2. The 5’ end of the mRNA binds to the ribosome using a ribosome binding sequence (RBS) 3. The large ribosomal subunit is added. The initiator tRNA will be in the Psite.
There are several types of chromosomal mutations that alter the structure of the c'some.
match the definition with the mutation:
a. deletions
b. duplication
c. inversion
d. translocation
1. part of c'som in reverse order
2. part of c'some is copied
3. part of c'some is moved to a new location
4. part of c'some is lost
a is 4
b is 2
c is 1
d is 3
In a pedigree, what shaped are the male and female? what colors are the affected, unaffected and carrier?
i can pull up a pedigree is needed
Male: square
Female: circle
Affected: green
Unaffected: white
carrier: half white and half green
A germ line with 36 total chromosomes produces ___ gametes that will have ___ chromosomes each.
4, 18
What post-transcriptional modifications are made in eukaryotic cells?
5' cap protects from degradation and Participates in the initiation of translation. Poly A tail protects from degradation and is involved in the nuclear export process. Splicing removes introns
What are the 3 steps of elongation?
1. Next charged tRNA enters the A site assisted by an elongation factor (EF-Tu) 2. A peptide bond is formed between the amino acid in the P site and the amino acid in the A site 3. Translocation of the ribosome occurs and the process can continue. An accessory factor (EF-G) helps with this.