Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

AP Bio > From DNA to Proteins > Flashcards

From DNA to Proteins Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

Gene expression-

A

steps in which DNA in the genes code for proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Archibald Garrod-

A

studied rare genetic disease called alkaptonuria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

alkaptonuria

A

recessive disease in which affected individuals were unable to break down tyrosine, an amino acid. Instead, homogentisic acid accumulates in urine and
turns it black. Lacked the enzyme which breaks down homogentisic acid–Mutation in one gene is associated with the absence of this specific enzyme

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Beadle and Tatum-

A

studied the fungus Neurospora.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Neurospora Wild Type

A

individual with normal phenotype, which can grow

normally on simple growth medium/basic nutrients

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Mutant strain (produced by radiation)- Neospora

A

cannot make a substance such as an amino acid, can only grow if that substance is added to growth medium
o Each mutant strain had mutation at only one locus- each gene locus affected only one enzyme
Called this the one-gene, one-enzyme hypothesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Linus Pauling-

A

Mutation at single locus alters the structure of one polypeptide chain of hemoglobin, causing sickle cell anemia
o Therefore- we now conform to the one-gene, one-polypeptide chain hypothesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Ribonucleic acid, or RNA,

A

link between DNA to protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Differences between RNA and DNA:

A

o RNA is single stranded

o Contains the sugar ribose, not deoxyribose

o Base uracil substitutes for thymine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Transcription-

A

the “copying” of the template strand of DNA and formation of RNA. Forms three types of RNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

three types of RNA

A

mRNA, tRNA, rRNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Messenger RNA (mRNA)-

A

single, uncoiled strand of RNA that carries information for making a protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Transfer RNA (tRNA)-

A

single strand of RNA that folds back
on itself to form a specific shape. Each tRNA bonds to
one type of amino acid and carries it to the ribosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Ribosomal RNA (rRNA)-

A

globular RNA that is part of the ribosomes of RNA and helps catalyze protein synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Differences between transcription and DNA replication:

A

Only part of the DNA molecule is
used as a template
o Enzyme
RNA polymerase is used as opposed to DNA polymerase
o Results in one free RNA strand, not a double helix
Transcription happens constantly–DNA replication happens during S of cell cycle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Initiation: (transcription)

A

first stage of transcription
a. RNA polymerase attaches to promoter- region in
DNA that is not transcribed, contains the sequence
TATA (TATA box)
b. RNA polymerase then unwinds the DNA and initiates transcription

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Elongation: (transcription)

A

second stage of transcription
a. RNA polymerase assembles RNA nucleotides using
1 strand of the DNA as a template
b. Occurs in
5’ to 3’ direction (new strand is made in 5’ to 3’ direction
like in replication)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Termination: (transcription)

A

third stage of transcription
RNA polymerase reaches a special sequence of
nucleotides that serve as a termination point
In eukaryotes- often contains the DNA sequence AAAAAAA
RNA polymerase releases the DNA template and the new RNA strand

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

In eukaryotic cells, each new molecule of mRNA is only what? what does this necessitate?

A

“pre-

mRNA”- must be modified before it can code for proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Modification of mRNA–5’ end

A

A modified GTP (guanosine triphosphate- or a guanine nucleotide with two extra phosphate groups) is added to the 5’ end to form a 5’ cap. Provides stability to new mRNA and a point of attachment for the ribosome.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Modification of mRNA–3’ end

A

3’ end of mRNA- 150 – 200 adenine nucleotides are added- poly-A
tail (-A-A-A….A-A-3’)
o Provides stability
o Controls movement of mRNA across the nuclear envelope

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

heterogenous nuclear RNA,

A

Pre-mRNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Alternative splicing-

A

Different exons can be kept in or snipped
out- will change the types of proteins that are produced. Explains how human cells can make hundreds of
thousands of proteins from only about 20k genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Exons-

A

sequences that express a code for a polypeptide. exported from nucleus.

25
Q

Introns-

A

intervening base sequences that must be removed before translation–stay in the nucleus

26
Q

Small nuclear ribonucleoproteins, or snRNPs,

A

delete out the introns and splice the exons

27
Q

Translation-

A

information found in mRNA is used to specify the amino acid sequence of
a polypeptide

28
Q

codons

A

The mRNA is read as codons- sequences of three consecutive bases of mRNA which specifies one amino acid

29
Q

codon code

A

Code is called triplet code because each codon consists of three nucleotides. All of the codons collectively form the genetic code

30
Q

cracking of genetic code

A

By 1967, the genetic code was “cracked”- scientists had
identified the amino acids for all 64 possible codons. The genetic code is universal- the same codons code for the same amino acids in all organisms. Since there are 64 possible codons and only 20 amino acids,
more than one codon specify certain amino acids

31
Q

anticodon

A

A particular tRNA can recognize a specific codon because it has a sequence of three bases, called the anticodon, that is complementary to the mRNA codon, forming hydrogen bonds with one another.

32
Q

Wobble effect-

A

The codon- anticodon interactions are not as strong for the third base in a codon

33
Q

Stop codons

A

UAA, UAG, UGA

34
Q

start codons

A

AUG

35
Q

effect of binding of anticodon

A

The amino acids carried by the tRNA can then be linked

together by peptide bonds in the order specified by the sequence of codons in the mRNA.

36
Q

Ribosomes

A

the site of translation
Consist of two subunits, small and large
Each is made of proteins and rRNA
During translation, the mRNA molecule fits between the two subunits
Contain 2 binding sites for tRNA: P, A, (and E)

37
Q

Translation

A

mRNA moves out of nucleus to the cytoplasm. Requires the coordinated functioning of protein and RNA components of the ribosomes, mRNA, and amino acids linked to tRNAs.

38
Q

tRNA action translation

A

Folds on itself to form three or more loops of unpaired nucleotides
Bottom loop contains an anticodon- 3 bases at bottom of molecule that will complementary base pair with the
codon found on the mRNA
Each kind of tRNA binds to a specific type of amino acid at the three prime top of the molecule
SEE DIAGRAM

39
Q

P site-

A

peptidyl site-tRNA holding growing polypeptide chain binds here

40
Q

A site-

A

aminoacyl site- tRNA delivering the next amino acid in the sequence binds here

41
Q

E site-

A

Exit site–tRNA exits here after dropping off its amino acid

42
Q

Initiation-

SEE DIAGRAM

A

first stage of translation:
The small ribosomal unit binds to the five prime end of the mRNA
An initiator tRNA binds to an mRNA at the start
sequence AUG. The initiator tRNA carries with it the
amino acid met
The large ribosomal unit binds to the small unit. The
initiator tRNA occupies the P site

43
Q

initiation complex

A

ribosome + mRNA + tRNA

44
Q

Elongation-

SEE DIAGRAM

A

second stage of translation:
a. A new tRNA bearing an amino acid binds to the A site of the ribosome.
b. Methionine is removed from the first tRNA and
attaches to the amino acid on the newly arrived tRNA
That first tRNA is then released into the cytoplasm
where it can once again bind to its amino acid

Meanwhile, the second tRNA can now move from the
A site into the vacated P site. The A site is now open, exposing the next codon. A new tRNA carrying a new amino acid enters the A site. The two amino acids in the P site bind to this new amino acid, forming a chain of 3 amino acids. This continues over and over, and the chain elongates by one amino acid at a time- dictated by the codons in the mRNA.

45
Q

Termination-SEE DIAGRAM

A

Ribosome encounters a “stop” codon. No tRNA molecule binds
Instead, a release factor (special protein) binds to A site
Therefore, when the tRNA in the P site separates from
the amino acid, the newly synthesized polypeptide chain is free

46
Q

What happens after translation has completed?

A

amino acids of the polypeptide chain can associate to form secondary and tertiary structures

47
Q

polysomes-

A

clusters of many ribosomes translating an mRNA transcript at the same time. found in bacterial cells that rapidly use or secrete proteins.

48
Q

Mutation-

A

change in the nucleotide sequence of DNA. not every mutation causes an observable change (some codons code for same amino acids, change in eye color in an skin cell). Mutations provide diversity

49
Q

Base substitution-

A

change in only one pair of nucleotides

50
Q

Missense mutations-

A

Base substitution. replacement of one amino acid by another

Can alter active site of enzymes

51
Q

silent mutation-

A

Base substitution. codes for the same amino acid/no observable change

52
Q

Nonsense mutations-

A

Base substitution. convert a code for an amino acid into a stop codon correct protein can’t be produced

53
Q

Frame shift mutation-

A

one or two nucleotide pairs are inserted or
deleted from the molecule, altering the reading frame (sometimes more –not multiples of 3) Codons downstream from this mutation specify a new sequence of amino acids resulting in a new polypeptide chain

54
Q

Transposons, or transposable genetic elements-

A

DNA sequences that jump from one area into the middle of a gene
Can alter the timing of the gene or block its activity
Discovered by Barbara McClintock- noticed that certain genes in corn would spontaneously turn on or off
Transposons require an enzyme transposase for incorporation into a new location
Most are retrotransposons

55
Q

retrotransposons

A

form copies of itself by producing an RNA intermediate, then an enzyme called reverse transcriptase forms DNA from that RNA and the DNA jumps into a gene

56
Q

Causes of Mutations

A

Spontaneous or mutagens

57
Q

Spontaneous mutations

A 
Mistakes in
DNA replication
• Defects in
mitotic or meiotic separation
• Hot spots
58
Q

Hot spots-

A

areas of DNA that are more likely than others to mutate–generally areas that have
stretches of repeated nucleotides

59
Q

Mutagens-

A

anything that causes a mutation
* Radiation

• Chemical mutagens can modify bases, leading to
mistakes in base pairing
- Although mutations in the somatic cells cannot be passed on to offspring,
some mutations can lead to cancer. In addition, many mutagens are
carcinogens-agents that can cause cancer

AP Bio (35 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions