genes Flashcards
RNA differs from DNA in that RNA:
contains ribose as its sugar
contains uracil instead thymine
if one strand of a DNA molecule has the sequence of bases 5’-ATTGCA-3’, what would the other strand be
3’-TAACGT-5’
a particular triplet of bases in the coding sequence of DNA is AGT. the corresponding codon for the mRNA transcribed is
UCA
A recessive allele on the X chromosome is responsible for red-green colour blindness in humans. A woman with normal vision whose father is colour-blind marries a colour-blind male. What is the probability that this couple’s son will be colour-blind?
50%
In a population which is in Hardy-Weinberg equilibrium, the frequency of the allele a is 0.4. What is the percentage of the population which is heterozygous Aa for this allele?
0.48%
one major difference between prokaryotic genes and eukaryotic genes
prokaryotic genes generally have introns and exons
the pairing of purines with pyrimidines in DNA results in
formation of the base pairs A to T and C to G
what is Chargaff’s rule
DNA should have a 1:1 ratio
what is transcription
process of making RNA from DNA
what is translation
process of making RNA into protein
how many types of RNA polymerase has prokaryotic systems
one
what do eurkaryotic systems use RNA polymerase II for
production of mRNA encoding proteins
eukaryotic RNA require extensive processing before
translation
new amino acids are carried into the ribosome linked to
tRNA
regarding translation - the synthesis process is carried out by
the ribosome
regarding translation - what is the smallest subunit of the ribosome
mRNA
regarding translation - where is the growing site for the polypeptide
P or A
what is a karyotype
an ordered display of the pairs of chromosomes from a cell. karyotyping shows that the chromosomes are normal in number and appearance
how many sets of chromosomes are in a diploid cell
two sets of chromosomes
how many sets of chromosomes are in a A gamete (sperm or egg) cell
single set of chromosomes
for humans, what is the haploid number
23
what does allele frequency mean
different versions of the same gene
what is a genotype
genetic makeup of an organism
what is a phenotype
physical makeup of an organism
(expression of the genotype)
what is the goal of a testcross
to tell the genotype of an individual with the dominant phenotype
why did gregor mendel use pea plants
reproduce quickly
easily control how they mate
achieve large number of offspring
easy traits to study
what is the locus of a gene
position of the gene on a chromosome
what is mendels law of segregation
alleles pairs separate during gamete formation, and reunite randomly at fertilization
what is mendels law of independent assortment
during meiosis, two genes of a pair sort independently into gametes, regardless of how other chromosomes are sorted
what is epistasis
a gene at one locus alters the phenotype expression of a gene at a second locus
- One gene determines the pigment colour (with alleles B for black and b for brown).
- The other gene (with alleles C for colour and c for no colour) determines whether the pigment will be deposited in the hair.
describe morgans fruit fly experiment
Morgan mated male flies with white eyes (mutant) with female flies with red eyes (wild type).
The F1 generation all had red eyes.
The F2 generation showed the 3:1 red:white eye ratio, but only males had white eyes.
Morgan determined that the white-eyed mutant allele must be located on the X chromosome.
Morgan’s finding supported the chromosome theory of inheritance.
what does deletion do
removes a chromosomal segment
what does duplication do
repeats a chromosomal segment
what does inversion do
reverses a segment within a chromosome
what does translocation do
moves a segment from one chromosome to another
what is natural selection
individuals with certain heritable characteristics survive and reproduce at a higher rate than other individuals
what is the hardy-weinberg principle
Describes a population that is not evolving.
If a population does not meet the criteria of the Hardy-Weinberg principle, it can be concluded that the population is evolving
