Mcat Biology Lecture 2

Front 1

____ - tending to change an organism even more

Back 1

Forward mutation

Front 2

____ - tending to revert the organism back to its original state

Back 2

Backward mutation

Front 3

Translation ends when a stop codon is reached in a step called ____.

Back 3

Termination

Front 4

In ____ sugars, lipids or phosphate groups may be added to amino acids.

Back 4

post-translational modifications

Front 5

____ - A series of DNA nucleotides that generally codes for the production of a single peptide, mRNA, rRNA, or tRNA

Back 5

Gene

Front 6

# of copies of genes for
Eukaryotes-
Prokaryote-

Back 6

Some genes have more than 1 copy.
1 copy

Front 7

Genome-

Back 7

The entire DNA sequence of an organism.

Front 8

____ of gene expression is that DNA is transcribed to RNA, which is translated to amino acids forming a protein.

Back 8

The Central Dogma

Front 9

____ - a polymer of nucleotides, differ from each other only in their nitrogenous bases

Back 9

DNA, deoxyribonucleic acid

Front 10

T, A, G, C

Back 10

Thymine
Adenine
Guanine
Cytosine

Front 11

Purine

Back 11

Two ring structures, Adenine & Guanine

Front 12

Pyrimadine

Back 12

Single ring structures Rhyamine and cytosine
Uracil replaces Thyamine in RNA
"Y for Pyrimidine"

Front 13

Each nucleotide is bound to the next by a ____ between the 3rd carbon of one deoxyribose and the ____ of a single strand of DNA with a ____ directionality.

Back 13

Phosphodiester bond
phosphate backbone
5'->3' directionality

Front 14

5' & 3' indicate?

Back 14

the carbon numbers on the sugar

Front 15

end 3' carbon is attached to?

Back 15

an -OH group

Front 16

end 5' carbon is attached to?

Back 16

a phosphate group

Front 17

In a living organism 2 DNA strands lie side by side in opposite 3'-5' directions, ____.

Back 17

antiparallel

Front 18

hydrogen bonding in DNA

Back 18

Base-pairing (bp)

Front 19

What are the complementary bases in DNA, # of H bonds

Back 19

Specific purine - pyrm pairs
T
A -- T & A have 2H bonds and these bind together
G
C -- G & C have 3H bonds and these bind together

(remember Uracil replaces Thyamine in RNA)

Front 20

____ - distinct bound complementary strands of DNA shape.

Back 20

double helix

Front 21

DNA (Struct)

Back 21

A polymer of nucleotides, each nucleotide has 3 parts,
The phosphate group
5-carbon sugar
The nitrogenous base

Front 22

____ - When a new DNA strand is created it contains (1) strand from the original DNA and 1 newly synthesized strand.

Back 22

Semi Conservative (DNA Replication)

Front 23

____ - from the origin, two replisomes proceed in opposite directions along the chromosome.

Back 23

bidirectional (process)

Front 24

____ proceeds in both directions from an origin. Each direction produces a leading and lagging strand.

Back 24

DNA replication

Front 25

DNA polymerase requires ____ to get started.

Back 25

RNA primer

Front 26

____ - the enzyme that builds the new DNA strand, cannot initiate a strand from 2 nucleotides, but can only add nucleotides to an existing strand.

Back 26

DNA polymerase

Front 27

approx 10 ribonucleotides long that initiates the strand. Created by an RNA polymerase.

Back 27

(RNA) primer

Front 28

Replications (5) Steps -

Back 28

1. Helicase unzips double helix.
2. RNA polymerase builds a primer.
3. DNA polymerase assmbles the leading & lagging strands.
4. The primers are removed.
5. Okazaki fragments are joined.

Front 29

Interrupted strand -
Continuous Strand -

Back 29

Lagging strand
Leading strand

Front 30

The lagging strand is made from a series of disconnected strands called _____.

Back 30

okazaki fragments
100-200 nucelotides in Eukaryotes
1000-2000 nucleotides in Prokaryotes

Front 31

Since the formation of one strand is continuous and the other fragmented, the process of replication is said to be ____.

Back 31

semidiscontinuous.

Front 32

____ - repeated (6) nucleotide units from 100 to 1000 units long that protect the chromosomes from being eroded through repeated rounds of replication.

Back 32

telomeres

Front 33

DNA VS RNA
-sugars
-# of strand
-different bp
-process it undergoes to form
-where it occurs

Back 33

DNA // RNA
deoxyribose // ribose
doublestranded // single stranded
thyamine // uracil
replication // transcription
in nuc, mito & matrix // also in cytosol
1 major type // 3 major types

Front 34

____ - RNA manufacturing process from a DNA template.

Back 34

Transcription

Front 35

deoxy vs RNA, name from?

Back 35

carbon #2 on the pentose is not "deoxygenated" (it has a hydroxy group attached)

Front 36

____ - delivers the DNA code for amino acids to the cytosol where the proteins are manufactured.

Back 36

mRNA (messenger RNA)

Front 37

____ - combines w/ proteins to form ribosomes
Synthesized in the nucleolus

Back 37

rRNA
(ribosomal RNA)

Front 38

____ - collects amino acids in the cytosol and transfers them to the ribosomes for incorporation into a protein.

Back 38

tRNA
(transfer RNA)

Front 39

Transcription requires a ____.
Replication requires a ____.

Back 39

T -> promoter
R -> primer

Front 40

____ - A spot on the DNA that tells RNA polymerase where to begin transcription.

Back 40

promoter

Front 41

____ - a short piece of RNA that jump starts replication.

Back 41

primer

Front 42

____ - the beginning of transcription.

Back 42

initiation

Front 43

Only the ___ of the DNA double helix is transcribed. The ___ resembles the universal code sequence of RNA.

Back 43

template strand
coding strand

Front 44

____ - the end of transcription.

Back 44

Termination

Front 45

In ____ of trascription, RNA polymerase transcribes only 1 strand of the DNA nucleotide sequence into a complementary RNA nucleotide sequence.

Back 45

elongation

Front 46

For all cells most regulation of gene expression occurs at the level of transcription via proteins called ____. ____ bind to DNA close the promoter and either activate or repress the activity of RNA polymerase.

Back 46

Activators
Repressors

Front 47

____ - A sequence of bacterial DNA containing an operator, a promoter and related genes. The genes of an ____ are transcribed on one mRNA. Genes outside the ____ may code for activators and repressors.

Back 47

operon
operon
operon

Front 48

____ - The initial mRNA nucleotide sequence arrived at through transcription.

Back 48

primary transcript

Front 49

protection from exonucleases

Back 49

poly A tail

Front 50

Serves as an attachment site in protein synthesis and protection against degradation by exonucleases

Back 50

5' cap

Front 51

The primary transcript is cleaved into these before leaving the nucleus.

Back 51

Introns & Exons

Front 52

Enzyme-RNA complexes called small nuclear ribonucleoproteins ____ recognize nucleotide sequences at the ends of the introns.

Back 52

SnRnp's
"snurps"

Front 53

Introns remain in the ____ and exons exit the ___ to be ____.

Back 53

nucleus
nucleus
translated

Front 54

Most of a typical gene consists of ____ removed by ____ in the ____.

Back 54

introns
SnRNP's
nucleus

Front 55

To ____ the DNA means to separate the two strands of the double helix.

Back 55

denature

Front 56

DNA prefers to be (single vs double) & will look for a _____ partner .

Back 56

double stranded
complementary partner

Front 57

____ of DNA will spontaneously associate with their original partner or any other complementary nucleotide sequence.

Back 57

Separated strands

Front 58

Nucleic Acid hybridization -

Back 58

DNA-DNA
DNA-RNA
RNA-RNA

Front 59

____ enable scientists to identify nucleotide sequences by binding a known sequence with an unknown sequence.

Back 59

Hybridization techniques

Front 60

Restriction enzymes

Back 60

to digest (cut) nucleic acid only at certain nucleotide sequences along the chain.

One method bacteria use to defend themselves from viruses is to "cut" the viral DNA into fragments with ____.

Front 61

Palindromic (sequence)

Back 61

4-6 nucleotides, read the same forward and backward

Typically a restriction site, where the virus is "cut" is a

Front 62

recombinant DNA

Back 62

artificially recombined. 2 DNA fragments cleaved by the same endonuclease can be joined together regardless of the origin of the DNA.

Front 63

vector

Back 63

what you use to place DNA within the bacteria.
Typically a plasmid or sometimes an infective virus.

Front 64

Include a gene with the original vector that has resistance to antibiotics, then flood with antibiotics and the bacteria without the vector die off. Voila!
- _____

Back 64

screened

Front 65

____ is just DNA reverse transcribed from mRNA. The great thing about ____ is that it lacks the introns that would be found normally in eukaryotic DNA.

Back 65

cDNA (complementary DNA)
cDNA

Front 66

The radioactively labeled complementary sequence of the desired DNA fragment ____ is used to search the library.

Back 66

probe

Front 67

____ is a fast way to "clone" DNA.

Back 67

PCR (polymerase chain reaction)

Front 68

A ____ identifies specific sequences of DNA by nucleic acid hybridization. Cuts DNA at certain restriction sites and separated by length via gel electrophoresis

Back 68

southern blot
anode (+)
cathode (-)
unlike galvanic cells

Front 69

A ____ identifies specific sequences of RNA by nucleic acid hybridization.

Back 69

Northern blot

Front 70

____ - detects a protein w/ antibodies

Back 70

western blot

Front 71

____ analysis identifies individuals as opposed to identifying specific genes.

Back 71

Restriction fragment length polymorphisms (RFCP)

Front 72

Start codon

Back 72

AUG

Front 73

Stop codon
(termination codon)

Back 73

UAA, UAG, UGA
(Signal an end to protein synthesis)

Front 74

3 consecutive nucleotides on a strand of mRNA.

Back 74

codon

Front 75

Genetic code is ____.

Back 75

Almost universal
(i.e. nearly every living organism uses the came code)

Front 76

___ - any single series of 3 nucleotides will code for 1 and only 1 amino acid.

Back 76

unambiguous

Front 77

___ - more than one series of 3 nucleotides may code for any amino acids.

Back 77

degenerative

Front 78

___ - the process of protein synthesis directed by mRNA.

Back 78

Translation

Front 79

Set of nucleotides that is complementary to the codon. (tRNA contains this)

Back 79

anticodon

Front 80

rRNA with protein makes up the ____, which provides the site for translation to take place.

Back 80

ribosome

Front 81

note that the ____ dont add up
40 + 60 = 80

Back 81

sedimentation coefficients

Front 82

special organelle like the "nucleus" of the nucleus

Back 82

nucleolus

Front 83

The ribosome is composed of these, made from rRNA and many separate proteins.

Back 83

small and large subunits

Front 84

Prokaryote subunits -
combined sedimentary coefficient -

Back 84

30s, 50s
70s

Front 85

Eukaryote subunits -
combined sedimentary coefficient -

Back 85

40s, 60s
80s

Front 86

A tRNA possesing the 5'-CAU-3' anticodon sequesters the amino acid methionne and settles in at the ____. This is the signal for the large subunit to join and form the ____. This process is termed ____.

Back 86

P site (peptidyl site)
initiation complex
initiation

Front 87

3 steps of translation -

Back 87

initiation
elongation
termination

Front 88

Mutations are ____. Mutations in ____ are not passed to ____; mutations in ____ are.

Back 88

rare
somatic cells
offspring
germ cells

Front 89

____ - a 2nd type of point mutation that may result in a frameshift mutation.

Back 89

insertion or deletion

Front 90

A ____ results when the deletions or insertions occur in multiples other than 3.

Back 90

frameshift mutation

Front 91

Genetic code is read in groups of ____ in translation.

Back 91

3 nucleotides

Front 92

A base-pair mutation that alters the codon and causes a different amino acid to appear in the sequence.

Back 92

missense mutation

Front 93

A basepair substitution or an insertion or deletion mutation that creates a stop codon.

Back 93

nonsense mutation

Front 94

Physical or chemical agents that induce mutations above the frequency of spontaneous mutations.

Back 94

mutagens

Front 95

A mutation that changes a single base-pair of nucleotides in a double strand of DNA.

Back 95

point mutation

Front 96

____ results when one base-pair is replaced by another.

Back 96

base-pair substitution mutation

Front 97

A 20 amino acid sequence near the front of the poly peptide is recognized by protein -RNA signal recognition particle (SRP) that carries the entire ribosome complex to a receptor protein on the ER.

Back 97

signal peptide

Front 98

The tRNA that carried methione moves to the ____ site where it can exit the ribosome.

Back 98

E site

Front 99

DNA segments that can excise themselves from a chromosome and reinsert themselves at another location.

Back 99

Transposon
(transposable elements)

Front 100

The orientation of a section of DNA is reversed on a chromosome.

Back 100

Inversion

Front 101

When a segment of DNA from one chromosome is inserted into another chromosome the resulting mutation is called a ____.

Back 101

translocation

Front 102

When a portion of the chromosome breaks off, or when a portion of the chromosome is lost during homologous recombination and/or crossing over events.

Back 102

deletions

Front 103

____ occur when a DNA fragment breaks free of one chromosome and incorporates into a homologous chromosome.

Back 103

duplications

Front 104

Genes that cause cancer -
Mutagens that can cause cancer -

Back 104

Oncogenes

Carcinogens

Front 105

Ocogenes where originally ___ that mutated.

Back 105

proto-oncogens

Front 106

___ change an organism even more from its original state.

Back 106

forward mutation

Front 107

____ tending to revert the organism back to its original state.

Back 107

backward mutation

Front 108

original state of an organism

Back 108

wild type

Front 109

Southern Blot "recipe"

Back 109

1. chop up some DNA
2. use an electric field to spread out pieces according to size.
3. Blot it onto a membrane
4. add a radioactive probe made from DNA or RNA
5. Visualize w/ radiographic film

Front 110

Translation begins on a free floating ____. A signal peptide at the beginning of the translated polypeptide may direct the ____ to attach to the ER, in which case the polypeptide is injected to the lumen. Polypeptides injected into the lumen may be secreted from the cell via the ____ or may remain partially attached to the ____.

Back 110

ribosome
ribosome
golgi
membrane

Front 111

In the ______ step of translation, a tRNA with its corresponding AA attaches to the ___ site at the expense of ____ CTP

Back 111

elongation
A site