exam 1 Flashcards
what is the definition of genetics?
the science of dealing with heredity and variation, seeking to discover laws governing similarities and differences in individuals related by decent
what is the definition of animal genetics?
the study of the principles of inheritance in animals
what is the definition of animal breeding?
the application of the principles of animal genetics with the goal of improvement of animals
what is the purpose of animal breeding?
to genetically improve the economic efficiency of livestock production
what is the purpose of selection?
to improve economic merit through genetics
what is selection?
the determination of parents of the next generation
what does natural selection seek?
genetic fitness
what was the first domesticated animal?
dog
who is know as the father of animal breeding?
Robert Bakewell
what are some effects of inbreeding?
- allows to mate genetically similar animals
- increases homozygosity
- improves uniformity
what did Robert Bakewell use inbreeding for?
the “purebred” concept
why focus on males when breeding a herd of cattle?
they produce more offspring
what test did Robert Bakewell develop an early version of?
bull progeny test
what did domestication do for civilization?
- they dont have to hunt and can spend that time on other things
- allowed civilization to happen
- during drought, they could still eat and keep life going
what were the three major events that led to the development of modern genetics?
- darwin published the origin of species
- mendel publishes experiments in plant hybridization
- miescher isolates nucleic acids from cells
why is a gene so much bigger than an mRNA?
the mRNA has had its’ introns removed
where does splicing happen?
the nucleus
what are two benefits of splicing?
- facilitates nuclear export
- helps with the stability of the molecule
what are the three RNA modifications?
intron splicing, 7 methylguanosinn cap, and poly-A tail
what roles does a 7 methylguanosine cap serve in protein synthesis?
found at the nucleus/ 5’ end to protect RNA from degradation, increases stability, allows for easy binding to the subunit of the ribosome
what protein is central to both the initiation and the elongation of transcription?
RNA polymerase
In the cell, what determines which DNA strand is transcribed?
a promoter
once a DNA strand is transcribed, what determines the open reading frame used for translation?
the position of the start codon (AUG)
where does transcription end?
the poly-A tail (AAA), 3’ end
where does translation end?
the stop codon (UGA, UAA, UAG)
in what direction are RNA polynucleotide transcripts assembled?
5’ to 3’
what orientation, with respect to the transcript, is the template DNA strand?
3’ to 5’
what direction does RNA transcription happen?
5’ - 3’
what has modifications? DNA replication or RNA transcription?
RNA transcription
what catalyzes RNA transcription?
RNA polymerase
what catalyzes DNA replication?
DNA polymerase
is a primer needed for DNA replication?
yes
is a primer needed for RNA transcription?
no
are all amino acids encoded by the same number of codons?
no
which amino acids are encoded by the most codons?
See, Leu, and ARG (6 codons each)
what amino acids are encoded by only one codon?
Met and Trp
what is special about the amino acid methionine?
start codon
what is the relationship between genes and traits?
genes code for specific traits
what is the relationship between genes and chromosomes?
genes are found on chromosomes
what is the relationship between alleles and genes?
alleles are alternate forms of genes
what is the relationship between DNA sequences and amino acid sequences?
DNA sequence determines amino acid sequence
what is a phenotype?
an observable characteristic
what are alleles?
alternate forms if a gene
what is independent assortment?
alleles of one gene separate into gametes randomly with respect to alleles of other genes
what are gametes?
reproductive cells containing only one copy of each gene
what is a homozygote?
one with two identical alleles of a given gene
what is a dominant allele?
the allele expressed in the phenotype of the heterozygote
what is a dihybrid cross?
a cross between two individuals both homozygous for two genes
how many chromosomes do humans have?
46
how many chromosomes do cattle have?
60
how many chromosomes do sheep have?
54
how many chromosomes do goats have?
60
how many chromosomes do dogs have?
78
how many chromosomes do cats have?
38
how many chromosomes do chickens have?
78
how many chromosomes do pigs have?
38
how many chromosomes do turkeys have?
80
how many chromosomes do horses have?
64
how many chromosomes do donkeys have?
62
how many chromosomes do camels have?
74
how many chromosomes do alapacas have?
74
how many chromosomes do llamas have?
74
how many chromosomes do rabbits have?
44
how many chromosomes do rats have?
42
how many chromosomes do mice have?
40
what are the four requirements for DNA to be genetic material?
- must carry info
- must replicate
- must allow for change
- must govern the expression of the phenotype
if there is an absence of a phenotype, what does that suggest? (Pp x Pp = 2Pp:1pp)
it suggests that homozygous dominant is lethal
what does helicase do in DNA replication?
unwinds the parental double helix
what do single strand binding proteins do in DNA replication?
they stabilize the unwound parental DNA
what direction is the leading strand in DNA replication synthesized?
5’ to 3’
what synthesizes the leading strand in DNA replication?
DNA polymerase
what are the three components that make up nucleotides?
nitrogenous bases, a phosphate backbone, and a five carbon sugar
what are the purine bases?
adenine and guanine
what are the pyrimidine bases?
thymine and cytosine
who discovered the structure of DNA? when?
Watson and Crick in 1953
what pair of nitrogenous bases has a double bond and what pair has a triple bond? which one is stronger?
A-T; C-G; triple bond
what is the purpose of DNA replication?
copying genetic info for transmission to the next gen
