Unit 2 Flashcards
Humans are diploid organisms, meaning
we have two alleles of each gene
We have two alleles because
you inherited one version of each chromosome from each parent
Each chromosome contains one allele of
each of the genes on that chromosome
Every gene in our genome is one of the ___ chromosomes
23
Gene (definition)
segment of DNA that is transcribed
Genes are _____
information; they do not do or make anything
Each member of the chromosome pair has the same genes (T/F)
true
Two alleles can be the same or different depending on the differences in
DNA sequences
Homozygous (definition)
when an individual’s two alleles are the same
Heterozygous (definition)
when an individual’s two alleles are different
All organisms have ____ containing ____ found in ____
cells; DNA; chromosomes
In a chromosome after duplication, there are 2 DNA molecules (T/F)
true
What bridges genotypes and phenotypes?
proteins
Most genes are ____-coding
protein
Is the protein-coding part the only part of a gene?
No. Most DNA in the genome do not code for proteins
Protein-coding genes have a ______ and a _____
coding region; noncoding region
Do genes make proteins?
No. They encode proteins.
If each chromosome version has an allele of the gene, are both alleles transcribed or just one?
Both alleles are transcribed AND both protein versions are produced
In the HD case study, what was the phenotype resulting from the difference in normal and HD alleles of the Hungtingtin’s gene?
the structure of the brain is a phenotype affected by this
The behavioral changes of HD patients (Case Study 1) are phenotypes affected by
the difference in normal and HD alleles of the Hungtintin’s gene
What are the two types of information in the genome?
instructions for how to make gene products
instructions for when, how much, and in what cells to transcribe genes
The transcription level of a gene varies depending on
cell type
development
environment
What is the key factor for controlling the level of transcription of a gene?
noncoding DNA
Why is regulation of transcription level important?
it allows different cells of the same organism to do different things
What is a gene regulatory switch?
a short sequence (5-20 base pairs) of DNA in the noncoding region
where transcriptional regulatory protein binds
Differences in transcriptional regulation are key to
the diversity of form among species
mRNA is produced by transcription from the coding DNA of a gene but not the noncoding DNA and this mRNA is translated to make a protein (T/F)
TRUE
mRNA is produced by transcription from both the noncoding and coding DNA of a gene and both of these mRNAs are translated to make proteins (T/F)
FALSE
What is a gene regulatory switch made of?
DNA only
Transcriptional regulatory proteins physically bind to
noncoding DNA
In a plant that has one teosinte parent and one maize parent (Case 3) ___ protein(s) is/are produced
both
Ignore
Ignore
Every human has two alleles of the lactase gene (T/F)
TRUE
Every human’s two lactase alleles are the same in each of their cells (T/F)
TRUE
Each lactase allele has a coding part and a noncoding part (T/F)
TRUE
The lactase alleles may differ in DNA sequences in their coding parts and/or noncoding parts (T/F)
TRUE
Mutations are referred to as
“the factory of variation production”
Mutation (definition)
a change in the nucleotides of a DNA molecule
Mutations are the original source of [all/most/some/no] genetic variation
all
Mutations occur when
mistakes are made in DNA replication or when DNA damage is not properly repaired
Mutations are [constantly/usually/rarely/never] occurring
constantly
In the absence of chemicals and radiation would mutation still occur?
Yes. Mutations occur randomly and are unavoidable. Chemicals and radiation are not common causes of mutation in nature or human populations
Does it matter where in the genome mutations occur?
Yes. Mutations in the coding region can affect amino acid sequence and mutations in the noncoding region can affect transcription levels.
Germ-line mutations (definition)
mutations that occur in the cells giving rise to sperm & egg cells (gametes)
Somatic mutations (definition)
mutations that occur in cells of the body during or after development
Which occurs more in multicellular organisms, somatic mutations or germ-line mutations?
Somatic mutations occur far more than germ-line mutations because we have more somatic cells than gametes.
Do somatic mutations pass down to offspring?
No
Do germ-line mutations pass down to offspring?
Possibly
Somatic mutations are mostly harmless aside from
cancer cells
Each gametes contains __ alleles of each gene
one
A typical mutation that occur in a human cell is likely to have ____ effect and likely to occur in ____ region
no effect; noncoding region
A mutation that occurs in the DNA of a skin cell on your back [can/cannot] be inherited by your children
cannot
