Nucleic Acids: Structure & Function Flashcards
1
Q
plasma membrane
A
single phospholipid bilayer
- contains proteins embedded into its bilayers
2
Q
nuclear membrane
A
continuous double phospholipid bilayer (inner & outer)
- contains proteins embedded into its bilayers
3
Q
nucleolus
A
responsible for ribosomal RNA processing and assembling ribosomal subunits
- site of ribosome assembly
4
Q
gene
A
a sequence of DNA—located at a specific locus—with a specific job or function
- made up of proteins
5
Q
metabolic pathway
A
a linked series of biochemical reactions that build up or break down a particular molecule
- product of one reaction is the substrate of the next reaction
6
Q
locus
A
location on a chromosome
7
Q
allele
A
gene sequence variability, which leads to variations in the gene function
8
Q
nuclear localization signal (NLS)
A
a short amino acid sequence that marks a protein for delivery to nucleus
9
Q
components of a nucleic acid
A
(1) phosphate group
(2) 5 carbon sugar
(3) nitrogenous base
10
Q
antiparallel
A
opposing orientation of nucleic acid strands that are hydrogen bonded to one another
- one strand = 5’ -> 3’
- another strand = 3’ -> 5’
11
Q
complementary base pairs
A
pair of bases that only bond to one another
- A + T or A + U = 2 H-bonds
- G + C = 3 H-bonds
12
Q
ribozyme
A
RNA enzyme that act as a catalyst by speeding up a chemical reaction
- contains uracil instead of thymine
13
Q
genotype
A
alleles of a gene
- determined by sequence of bases in its DNA
14
Q
phenotype
A
physical traits expressed according to a genotype
- product of proteins it produces
15
Q
central dogma
A
scheme for information flow in the cell: DNA S RNA S protein
16
Q
types of transportation through nuclear pores
A
(1) nuclear export signal (mRNA)
2) nuclear localization signal (lamin
17
Q
nucleotide structure
A
1’ - base
2’ - R (DNA or RNA) = OH or H
3’ - OH (polymer)
4’ - connect to 5’
5’ - phosphate
(1B 2R 3OH 45 5P)
18
Q
purine
A
class of small, nitrogen-containing, double-ringed bases found in nucleotides - bases: adenine & guanine
*linked juntos by 9 atoms
19
Q
pyrimidine
A
class of small, nitrogen-containing, single-ringed bases found in nucleotides - bases: cytosine, thymine OR uracil
*linked juntos by 6 atoms
20
Q
polymer properties
A
(1) condensation reaction
(2) phosphodiester bond
(3) sugar-phosphate backbone
(4) 5’ & 3’ ends
(5) primary structure depends on order of nucleotides
21
Q
primary structure
A
depends on order of nucleotides
- consists of sugar-phosphate backbone (phosphodiester linkages + sequence of 4 types of bases)
- RNA < stable than DNA
- supports catalytic activity in molecule
22
Q
secondary structure
A
depends on H-bonds
- result of complementary base pairing btwn purine & pyrimidine bases
- section where fold occurs =unpaired bases + stem-&-loop configuration
23
Q
nucleic acid functions in DNA
A
make up genetic material
24
Q
nucleic acid functions in RNA
A
(1) gene expression (mRNA, tRNA, rRNA, siRNA)
(2) ribozymes
(3) ATP & GTP
(4) genetic material in some viruses
25
Watson & Crick
credited for discovery of DNA structure
- used Rosalind Franklin's collected data but she was not credited
- basically trial & error
26
DNA structure
(1) double-stranded = secondary structure
(2) antiparallel
(3) self-perpetuating - can only be replicated/connected in 1 way
27
types of RNA
(1) messenger RNA, mRNA
(2) transfer RNA, tRNA
(3) siRNA
(4) rRNA
28
messenger RNA (mRNA)
complimentary to DNA
| - carry info required to manufacture proteins
29
ribosomal RNA (rRNA)
forms part of ribosome
- manufactured in nucleolus
- bind to proteins -> ribosomes
- machinery
*most RNA
30
transfer RNA (tRNA)
interacts w/ amino acids & RNA
31
siRNA
gets rid of mRNA
| - regulates translation
32
central dogma
scheme for info flow in cell
(1) DNA - info storage
TRANSCRIPTION
(2) mRNA - info carrier
TRANSLATION
(3) proteins - active cell machinery
[DNA -> RNA -> protein]
33
reverse transcription
RNA becomes DNA
34
translation
nonreversiable
35
types of proteins
(1) cytosolic proteins
| (2) lumenal proteins
36
genetic code property
must be triplet code
| - triplet code allows for more amino acids
37
reading frame
3 combo letters stand for specific amino acid
- always start w/ AUG (start codon)
- 3 stop codons
38
gene characteristics
(1) redundant
(2) unambiguous
(3) nearly universal
(4) conservative
39
redundant gene
more than 1 codon
all amino acids (except methionine & tryptophan) are coded by more than 1 codon
40
unambiguous gene
know codon, know amino acid
single codon never codes for more than 1 amino acid
41
nearly universal gene
all codons specify the same amino acids in all orgs
| - few minor exceptions
42
conservative
several codons specify the same amino acid
1st 2 bases in those codons are almost always identical
43
mutations
(1) single base change
(2) few bases change
(3) part of chromosome change
(4) whole chromosome changes
44
karyotype
spread of all chromosome
45
RNA world hypothesis
chemical evolution produced RNAs that could catalyze key reactions involved in their own replication & basic metabolism
46
nucleic acid
macromolecule composed of nucleotide monomers
47
nucleic acid properties
(1) polymer
(2) made up of nucleotides
(3) stores & processes info
(4) examples: DNA & RNA
48
types of nucleotides in living cells
(1) ribonucleotide (RNA)
| 2) deoxribonucleotide (DNA
49
ribonucleotides (RNA)
monomers of ribonucleic acid
- sugar: ribose
*more stable than DNA
50
deoxyribonucleotide (DNA)
monomers of deoxyribonucleic acid
- sugar: deoxyribose
- carries info required for org's growth & reproduction
51
phosphodiester linkage/bond
chemical linkage btwn adjacent nucleotide residues in DNA & RNA
- result of: condensation reaction
52
nucleic acid directionality
(1) 5' end = phosphate
(2) 3' end = hydroxyl
(3) base sequence always written in 5'-3' direction
(4) bases only added at 3' end of growing molecule
(5) primary
53
adenine triphosphate (ATP)
molecule consisting of adenine base, sugar & 3 phosphate groups that can be hydrolyzed to release energy
- universally used by cells to store & transfer energy
54
DNA points to prove (Watson/Crick)
(1) sugar phosphate backbone
(2) Erwin Chargaff empirical rules (# purines = # pyrimidines)
(3) DNA = helical (Rosalind Franklin)
55
complementary strand
new strand of RNA or DNA that has a base sequence complementary to template strand
5'-3'
56
template strand
original DNA strand
3'-5'
57
DNA double helix
(1) highly structured
(2) regular
(3) symmetric
(4) held together via H-bonds + hydrophobic interactions + phosphodiester bonds
58
hairpin
a stable loop formed by H-bonds btwn purine & pyrimidine bases on same strand
- reduces entropy of RNA molecules
- secondary structure in RNA
59
tertiary structure
3-D folding
- arises when secondary structures fold into more complex shapes
*not present in DNA
60
nucleus
info center of eukaryotic cells
- corporate headquarters
- design center
- library
- highly organized interior
61
nuclear lamina
lattice-like sheet of fibrous nuclear lamins
- type of intermediate filament
- lines inner membrane of nuclear envelope
- stiffens envelope
- organizes chromosomes
- defines organelle's overall shape & structure
62
nuclear envelope
separates nucleus from rest of cell
63
nuclear pore
opening in nuclear envelope
- connects inside of nucleus w/ cytoplasm
- molecules (mRNA & some proteins) pass through here
64
nuclear pore complex
large complex of dozens of proteins lining a nuclear pore, defining its shape & regulating transport through pore
65
zip code
molecular address tag
- marks them for transport through nuclear pore complex
- allows nuclear pore complex to open in some way that permits larger proteins & RNA molecule to pass through
66
RNA polymerase
enzyme that catalyzes the synthesis RNA molecules from ribonucleotides according to info provided by sequence of bases using a DNA template
67
exceptions to central dogma
(1) many genes code for RNA molecules that ≠ fcn as mRNAs -> translated into proteins
(2) info flows from RNA back to DNA
(3) reverse transcriptase
68
reverse transcriptase
enzyme that can synthesize double-stranded DNA from a single-stranded RNA template
- RNA virus infecting cells use this mode of synthesis
69
genetic code
set of all codons & their meanings
- rules that specify relationship btwn nucleotide sequence in DNA or RNA & amino acid sequence in proteins
- triplet code
70
reading frame
series of non-overlapping, 3-base-long sequence (potential codons) in DNA or RNA
71
start codon
AUG triplet in mRNA @ which protein synthesis begins
| - codes for amino acid, methionine
72
stop codon
any of 3 mRNA triplets (UAG, UGA, or UAA) that cause termination of protein synthesis
- signals protein = complete
- does not code for an amino acid
- ends translation
(aka) termination codon
73
mutation
any permanent change in an org’s DNA
- create new alleles
- modification in cell’s info archive
- alter DNA sequences that range in size from a single base pair in DNA to whole sets of chromosomes
74
point mutation
mutation result in change of single base pair in DNA
75
types of point mutation
(1) missense mutation
(2) silent mutation
(3) frameshift mutation
(4) nonsense mutation
76
missense mutation
point mutation that changes 1 amino acid for another w/in protein sequence
77
silent mutation
point mutation that changes codon sequence w/out changing amino acid that is specified
78
frameshift mutation
addition or deletion of nucleotide in a coding sequence that shifts the reading frame of mRNA
- alters meaning of all subsequent codons
79
nonsense mutation
point mutation that converts an amino-acid specifying codon into a stop codon
- large effect
- causes early termination of polypeptide chain
- often results in a non-fcnal protein
80
mutation categories
(1) beneficial
(2) neutral
(3) deleterious
81
beneficial mutation
mutation ↑ org fitness (ability to survive/reproduce) in certain environ
(ie) G-to-A mutation (beach habitats) camouflages mice
82
neutral mutation
mutation has no effect on fitness
(ie) silent mutation
83
deleterious mutation
mutation, allele, or trait that ↓ individual’s fitness
- harmful
(ie) cancerous cell chromosomes = aneuploidy + inversions + translocations + deletions + duplications
84
changes in chromosomes
(1) inversion
(2) translocation
(3) deletion
(4) duplication
85
inversion
mutation in which chromosome segment breaks from rest of chromosome, flips & rejoins in reversed orientation
86
translocation
attached to a different chromosome
87
deletion
chromosome segment is lost
88
duplication
additional copies of segment present
