Chapter 21 - Gene Expression Flashcards
copy of a segment of DNA that determines a gene that is then sent to the cytoplasm to then make a protein
RNA
what building block molecules are used to make proteins?
amino acids
Describe the DNA structure
“double helix”
long double stranded polymer
What does polymer mean?
that it’s made of building block molecule
before cells divide, what happens to DNA?
DNA condenses into butterfly shapes
What is the first step to gene expression?
Transcription
What is transcription?
converting information in DNA into RNA
sequence of bases that indicates where transcription should start
promoter
When does transcription stop?
when the enzyme reaches a termination (stop) sequence
what does mRNA stand for?
messenger RNA
‘coding’ segments that provide instructions for proteins
exon
noncoding segments
intron
20,000-25,000 genes produce > _________ proteins
100,000
Primary transcript can be edited in different ways to yield multiple mRNAs. This is called:
alternative splicing
converting the coded information in RNA into a protein
translation
translation is the switching of what?
“languages” from nucleotides to amino acids
carries DNA instructions for proteins out of the nucleus
mRNA
combines with proteins to form ribosomes
rRNA
What are ribosomes?
the sites of protein synthesis, made of RNA subunits
binds to an amino acid, then ferries the amino acid to sides on mRNA (“reading” the three base code)
tRNA
what is the removal of water called?
dehydration synthesis
DNA is a stable molecule, and the process of replication is highly precise, but ______ sometimes occur
errors
DNA replication is also known as what?
DNA synthesis
Change in DNA sequence caused by faulty replication
gene mutation
In cells destined to become gametes (sex cells), the mutation can be passed to _______
offspring
In point mutations, repair enzymes can recognize problems, cut the base out, stick in the correct base, and continue with transcription
true
additions of one or more bases
insertions
loss of one or more bases
deletions
flipping of sequence
inversions
copy a length of sequence or complete gene
duplications
change does not affect resulting amino acid sequence
silent mutation
there is a change in amino acid sequence, but it does not affect protein function
harmless mutation
new protein structure does not work as well
altered protein function
example of destruction of protein function
point mutation produces ‘stop codon’ in the wrong place
mutation causes improper folding which stops protein from functioning
what helps us see color?
opsin genes produce proteins to help us see color
Lots of primates lack a 3rd opsin gene but we have a 3rd opsin gene. How?
Within our DNA, an old opsin gene was duplicated and over many generations, one of these copies acquired small mutations that allowed it to detect different wavelengths of light. Human color vision is due to duplication from a long time ago
describe a gene
sequence of nucleotides on a segment of DNA that determines a particular protein
Genes come in pairs. One from each of these:
One from maternal and one from paternal source. We get 2 copies
What can occur when there is a point mutation when making sister chromatids?
A wrong letter can cause a mutation, however, repair enzymes can recognize problems, correct it, and continue with transcription
DNA polmerases making copies of two strands, resulting in a copy of sister chromatid. Each new copy is half of the old copy.
DNA replication/synthesis
A machine that reads DNA strands making a complementary version then another reads it backwards
DNA polymerase
What are ribosomes made out of?
rRNA
building blocks of protein
amino acid
Sequences of DNA that do not translate to proteins
introns
Difference between introns and exons
Segments that remain are exons, they exit the nucleus. Introns insert DNA
when you make a copy of your DNA to be exported out of the nucleus
alternative splicing
In alternative splicing, a single segment of DNA can make a slightly different _______, which can make slightly different _______
RNA; proteins
Process occuring in DNA -> RNA
transcription
Process occuring in RNA -> Protein
Translation
What is the tail of mRNA that complements the sequence?
anticodon
RNA polymerase is a machine that makes a copy of one strand of DNA. The copy is called _______
RNA
________ produced the protein and suddenly the monkey was able to see color.
mRNA
