Biology

Question 1

acidic amino acids

Answer 1

aspartate and glutamate

Question 2

basic amino acids

Answer 2

lysine, arginine, and histidine

Question 3

polar amino acids

Answer 3

serine, threonine, tyrosine, asparagine, and glutamine

Question 4

hydrophobic vs. hydrophilic amino acids

Answer 4

the acidic/basic/polar amino acids are hydrophilic, all others are hydrophobic

Question 5

cysteine and cystine

Answer 5

cystine is formed when cysteine is oxidized to form a disulfide bridge

Question 6

peptide bone formation

Answer 6

reaction of carboxylic group with amino group with a loss of water

Question 7

hydrolysis of protein

Answer 7

proteolysis, breaking of peptide chain using water

Question 8

amino acid important in alpha helix

Answer 8

proline

Question 9

solvation layer

Answer 9

shell around protein that interacts with solvent (water)

Question 10

isoelectric point

Answer 10

the point at which a molecule has no net charge, for an amino acid this occurs at the mean of the pKa’s

Question 11

isoelectric focusing

Answer 11

an amino acid will be very positive at very low pH and will migrate towards the isoelectric point, it will be negative at high pH and migrate towards isoelectric point

Question 12

how enzymes work

Answer 12

lower activation energy by stabilizing the transition state

Question 13

types of enzymes

Answer 13

hydrolyase - break chemical bonds with water
isomerase - moves bonds around
ligase - joins together
lyase - breaks bonds without water or oxidation
kinase - phophorylates from another molecule
oxidoreductase - redox
polymerase - addition of many molecules
phosphatase - removes phosphate
phosphorylase - transfers phosphate from inorganic
protease - breaks protein with hydrolysis

Question 14

active site model

Answer 14

lock and key - substrate and active site are perfecty complementary

Question 15

induced fit model

Answer 15

substrate and enzyme differ slightly and binding introduces conformation change in enzyme

Question 16

cofactor vs. coenzyme

Answer 16

same but a coenzyme is organic

Question 17

cooperativity

Answer 17

like sigmoidal hemoglobin curve, binding of additional substrates

Question 18

competitive inhbitor

Answer 18

same Vmax, larger Km

Question 19

non-competitive inhibitor

Answer 19

smaller Vmax, same Km

Question 20

uncompetitive inhibitor

Answer 20

binds to enzyme substrate complex, lower Vmax and Km

Question 21

absolute configuration at the alpha position

Answer 21

amino acids in humans are L, sugars are D

Question 22

proline special

Answer 22

kinks the chain, so it never appears in alpha helix

Question 23

semiconservative replication

Answer 23

one strand is used as a template and the other has new bases added to it

Question 24

euchromatin vs hetereochromatin

Answer 24

hetero - more dense, less transcribed genes

eu- less dense, more transcribed genes

Question 25

topoisomerase

Answer 25

prevents supercoiling of DNA downstream from helicase

Question 26

primase

Answer 26

adds an RNA primer to the growing strand

Question 27

DNA pol 1 and 3

Answer 27

both present in prokaryotes DNA pol 1 - adds nucleotides at RNA primer 5' to 3', also has exonuclease capabilities DNA pol 3 - fast and accurate, does most of transcription, also has proofreading

Question 28

differences between prokaryotic and eukaryotic replication

Answer 28

eukaryotic - several replication bubbles | prokaryotic - one site of replication, circular chromosome

Question 29

telomerase

Answer 29

adds telomeres to ends of chromosomes, usually only present in germ line, stem cells or white blood cells, also tumor cells

Question 30

missense mutation

Answer 30

one AA replaced with another

Question 31

loss of heterozygosity

Answer 31

loss of one allele result in hemizygocity, if other gene if affected, can lead to disease

Question 32

haploinsufficiency

Answer 32

one good gene is not enough for normal funciton

Question 33

methylation to distinguish strands

Answer 33

used in prokaryotes, parental is labeled with methylation, daughter strand is not, is able to distinguish the difference, eukaryotes differentiate using free 3' end or Okazaki fragments

Question 34

difference between DNA and RNA

Answer 34

DNA - no 2' hydorxyl group, less reactive, more stable

Question 35

monocistronic vs polycistronic

Answer 35

eukaryotes are mono, prokaryotes are poly, mono means one strand encodes for one gene, encodes for one protein

Question 36

heterogeneous nuclear RNA

Answer 36

made in the nucleus, immature or presursor to mRNA

Question 37

tRNA

Answer 37

has anticodon that binds to mRNA and adds to growing polypeptide chain

Question 38

rRNA

Answer 38

major component of ribosome, catalytic RNAs are called ribozymes

Question 39

fidelity of RNA/DNA

Answer 39

RNA pol makes more mistakes, no editing capabilities

Question 40

spliceosome

Answer 40

cuts out the introns and keeps exons, only present in eukaryotes

Question 41

RNA pol 1,2,3

Answer 41

1 - rRNA 2 - hnRNA 3 - tRNA in eukaryotes

Question 42

relationship between tRNA and amino acids

Answer 42

each tRNA corresponds to one amino acid but each amino acid may have many tRNAs

Question 43

wobble hypothesis

Answer 43

third amino acid of anticodon has some flexibility, allows for smaller number of tRNAs to be possible

Question 44

aminoacyl-tRNA synthetases

Answer 44

combines tRNA and amino acid, requires 2 ATP, allows for specific AA and tRNA to bind and activates AA for growing polypeptide chain

Question 45

subunits of ribosomes

Answer 45

50/30 in pro, 5.8/5/40/60 in eu

Question 46

degenerate code

Answer 46

there are repeats in the code for amino acids

Question 47

initiation and stop codons

Answer 47

initiation - AUG | stop - UAA, UAG, UGA

Question 48

snRNPs

Answer 48

involved in spliceosome in eukaryotes, occurs in the nucleus, removes the introns, also associated with snRNAs

Question 49

chaperones

Answer 49

helps proteins fold into their correct shape

Question 50

locus

Answer 50

where a gene is located on a chromosome

Question 51

alleles

Answer 51

a copy of a gene, one allele on each homologous chromosome

Question 52

incomplete dominance

Answer 52

neither dominant nor recessive, instead of white and red you have pink

Question 53

codominance

Answer 53

both alleles are expressed, but not blended, like blood type

Question 54

synaptonemal complex

Answer 54

forms in prophase I, connects the two homologous chromosomes

Question 55

natural selection, phenotypes and genotypes

Answer 55

natural selection only acts on phenotypes, not genotypes

Question 56

differential reproduction

Answer 56

individuals that reproduce more will be selected for, individuals who reproduce less will be selected against

Question 57

linkages in glycogen

Answer 57

alpha 1,4 linkages and alpha 1,6 at branch points

Question 58

nucleolus

Answer 58

ribosome factory in the nucleus and site of transcription

Question 59

localization sequence vs signal sequence

Answer 59

localization = nucleus, mitochondria and peroxisomes | signal sequence = secreted, plasma membrane, lysosome, ER, golgi