Bio Test 3 Flashcards
How many phosphates does AMP have?
one phosphate
How many phosphates does ADP have?
two phosphates
How many phosphates does ATP have?
three phosphates
What does the basic structure of a nucleotide contain?
nitrogenous base
sugar (5-carbon)
phosphate
nucleotides are subunits of what?
nucleic acids
What are the two major types of bases?
purines
pyrimidines
What are purines?
two rings
adenine (A)
guanine (G)
What are pyrimidines?
one ring
cytosine (C)
thymine (T)
uracil (U)
What are the two major 5 carbon sugars in nucleotides?
ribose
deoxyribose
What kind of phosphates are there?
AMP
ADP
ATP
a phosphodiester bond is just a what bond?
covalent bond
How do nucleic acids form?
the hydroxyl group of first nucleic acid covalentaly bonds to the phosphate group of the second nucleic acid
note that the base is not part of the bond
deoxyribonucleic acid (DNA) structure
building blocks: A, T, G, C
complementary base pairing
double strand (held together by hydrogen bond)
double helical structure
complementary base pairing
A pairs to T with 2 hydrogen bonds
G pairs to C with 3 hydrogen bonds
double helical structure
2 nm in diameter
10 base pairs per turn or .34 nm per turn
major or minor grooves
define antiparallel
two DNA strands
each chromosome is a ….
linear DNA molecule
humans have…
22 pairs of chromosomes + the sex chromosome
how long is each chromosome?
2 meters
law of segregation
two alleles for each trait separate during gamete formation
genes
what governs are inheritance of traits
alleles
different variations of gene account
genotype
is the actual genetic makeup (AA, Aa, or aa)
homozygous
individual trait that has two identical alleles (AA or aa)
heterozygous
individual trait that has two different alleles (Aa)
monohybrid cross
cross between parents that are heterozygous for a single trait
- true for all sexually reproducing organisms
law of independent assortment
alleles for different traits segregate and assort independently
- from dihybrid cross
- only true for genes on different chromosomes or separated by distance on same chromosome
dihybrid cross
cross between parents that are heterozygous for two traits (YyRr)
polygenic inheritance
- traits determined by multiple genes
- traits show continuous variation
- each gene makes small contribution to phenotype
- example: height
incomplete dominance
- don’t have clear dominant-recessive relationship
- cross between two heterozygous parents
- results in 1:2:1 ratio
codominance
- don’t have clear dominant-recessive relationship
- each allele of gene is expressed and determines phenotype
- example: human blood
- strong alleles show both phenotypes
human blood types are determined by what…
by the sugar molecule on the surface of the red blood cell
multiple alleles
human blood is example….just has multiple alleles
environmental factors
there are temperature sensitive alleles of certain genes
What is the sugar exhibited in blood type A?
galactosamine
What is the sugar exhibited in blood type B?
galactose
What is the sugar exhibited in blood type AB?
galactosamine and galactose
What is the sugar exhibited in blood type O?
none
replication process
opening DNA double helix (opens at ori) building a primer assembling complementary strands removing primer joining okazaki fragments
replication origin
span of 100 bp attract initiator protein have fewer hydrogen bonds and easy to open often A-T-rish stretch of DNA numerous in human, one in bacteria
semiconservative replication
When a DNA strand splits in half, the parent strands from the original DNA strand replicate and form two new daughter strands. Creates a new double-stranded DNA.
DNA polymerase III
copys DNA; uses primer or hydroxyl group to add nucleotides to RNA primer
DNA helicase
opens DNA for replication; unzips
DNA primase
comes in to make primer (RNA nucleotide; 10 bases long)
single-strand DNA-binding protein
stabilize single strand; prevents them from pairing back together
replication forks
- two replication forks are formed at each replication origin
- move in both directions
- move at rate of 1000 bp/sec in bacteria
- move at rate of 100 bp/sec in humans
DNA polymerase I
removes old primer and replaces it with DNA nucleotides
replication forks are asymmetrical or symmetrical?
asymmetrical
DNA ligase
join okazaki fragments together
the leading strand grows….
continuously
the lagging strand grows…
discontinuously (okazaki fragments)
telomere
- 6 bp repeats (TTAGGG)
- 10,000-15000 bases or 10-15 kb
- shortening/ replication
telomerase
enzyme that is complimentary to 6-bp repeats (TTAGGG); pairs very end and creates a template, and extends telomere longer so another okazaki fragment can be created
also linked with aging
telomerase is made up of what?
reverse transcriptase + telomere RNA
types of DNA damage
depurination
deamination
T-T dimer
accidental double-strand break
depurination
removes purine base so nucleic acid is missing one its main opponents
deamination
removes the amino group and leaves an oxygen in its place which then causes a mismatch
T-T dimer
caused by UV radiation; covalent bond between two thymines
accidental double-strand break
cause by UV radiation; repair usually cause a deletion of many genes
consequences of DNA damage
point mutation
deletion mutation
point mutation
caused by deaminated C, therefore is a U instead of a C and the new daughter strands brings in A instead of G
creates mutated replicated DNA and unchanged
deletion mutation
caused by depurinated A, therefore where there should be an A, there is none; so on the new daughter strand, we are just missing a gene
creates mutated replicated DNA and unchanged
3’ to 5’ exonuclease
when replication mistake occurs, this enzyme comes in and repairs it by taking off mismatched base and replacing with correct base
unrepaired DNA strand can cause what?
it can cause a mutated strand which then can cause a disease such as sickle cell anemia
error rates
1/10^7 replicated bp without repair
1/10^9 replicated bp with repair
