chromosomes
DNA is stored in what form in the nucleus?
chromatin
a heritable trait that varies among individuals is a ________
character
what types of viruses can infect bacteria/transfer DNA? Why is this important to scientists?
These are bacteriophages (phages). Genetic researchers can use these to add specific DNA into bacteria or other cells.
The expression of DNA can be summed up as ...
(central dogma of biology)
DNA to RNA to protein
(Gene expression)
What are the two categories of point mutations
substitutions and insertions/deletions.
what is the process of nondisjunction, and when does it occur?
It happens when chromosomes do not separate correctly during meiosis. Some gametes receive two copies of a chromosome and others may get none.
a variant of a character is a _______
trait
What did Watson and Crick determine about base pairing?
A purine must bind with a pyrimidine
- a two ring purine (A/G) must go with a single ring pyrimidine (T/C) to be the proper width of double helix
How many codons code for amino acids?
61, remember there are 3 stop codons.
the start codon met is an amino acid.
What occurs to create a nonsense mutation?
a substitution results in a change to the codon that codes for a STOP codon, often makes a non-functioning protein.
Which organisms are more susceptible to x-linked recessive disorders and why?
males because they are homozygous for the X chromosome
Explain the significance of the Law of Segregation.
Mendel's Law of segregation says that each gamete only receives one allele for each heritable character
The semiconservative model of DNA replication assumes that...
It means that new DNA have 1 old strand and one new strand. (old DNA is semi-conserved)
What has to occur before RNA polymerase synthesizes the RNA transcript?
The promoter must be bound by RNA polymerase II with the help of transcription factors.
Frameshift mutations are the result of ...
insertions or deletions that shift the reading frame and result in often very severe changes to the protein.
when chromatin condenses, what do we call it? What about the protein structures that DNA coils around to make chromatin?
heterochromatin, DNA coils around histones which create nucleosomes.
A monohybrid cross is a cross between what two genotypes? (give an example with whatever letters you would like)
Two heterozygotes like Hh and Hh.
DNA is only synthesized in the ___ to _____ direction by what type of protein?
5 to 3 by a DNA polymerase (usually pol III)
How is translation terminated?
A stop codon allows for a special release factor protein to bind to the ribosome A site. This adds a water to the polypeptide chain, releasing the protein.
missense mutations code for...
the wrong amino acid, but only affect a single amino acid.
What is an extranuclear gene and what is the pattern of inheritance for these genes?
What does epistasis describe and give an example where epistasis is at play.
It is when a gene of one locus affects the expression of a gene at a second locus. ex. Labrador retriever color
Two mechanisms for DNA repair that we covered in this chapter are... (explain)
Mismatch repair, changing out mismatched nucleotides (a-c) for example
Nucleotide excision repair uses a nuclease to cut out and replace damaged stretches of DNA
RNA processing must occur in what types of organisms and alter the mRNA in what 3 ways?
Eukaryotic organisms need pre-mRNA altered by attachment of the 5' cap and poly a tail (3').
RNA processing must also remove introns via splicing.
What causes mutations to occur, give 2 examples.
spontaneous mutations caused by errors in replication or recombination.
Also caused by mutagens like carcinogens.