Brainscape's Knowledge GenomeTM

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


See full index

Bio 184 > Unit 1 > Flashcards

Unit 1 Flashcards

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

What are the requirements of “genetic material”

A
  1. Can replicate
  2. Controls the expression of traits
  3. Ability to change/adapt
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Do polypeptides or DNA have more potential variation/different combinations?

A

Polypeptides

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

What is the nucleotide? What are its 3 components? What bond links them together?

A

The repeating structural unit of DNA and RNA

Phosphate group, Pentose sugar, nitrogenous base

Phosphodiester bonds

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

What is Chargaff’s rule?

A

% adenine = % thymine
% cytosine = % guanine

adenine + guanine (purines) = thymine + cytosine (pyrimidines)

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

What did Rosalind Franklin discover about the structure of DNA?

A

X-ray diffraction showed that DNA is helical with more than one strand. 10 base pairs per complete turn.

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

What direction do DNA strands go in?

A

A phosphate connects the 5’ carbon of one nucleotide to the 3’ carbon of another

Therefore, strand goes 5’ to 3’

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

What are some general DNA structural features?

A

•10 base pairs per complete twist
•the two strands are antiparallel
-one runs in the 5’ to 3’ direction and the other goes 3’ to 5’
•the helix is primarily in right-handed in the B form

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

How is the double-bonded structure of DNA stabilized?

A
  1. Hydrogen bonding between complementary bases (A-T is 2 hydrogen bonds, C-G is 3 hydrogen bonds)
  2. Base stacking (flattened regions face each other)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What two asymmetrical grooves are on the outside of the helix?

A
  1. Major groove
  2. Minor groove
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What different forms of the DNA double helix can form?

A

•B-DNA, the predominant form found in living cells
•A-DNA and Z-DNA, under certain in vitro conditions

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

What are some of the features of A-DNA?

A

•right handed helix
•11 bp per turn
•occurs under conditions of low humidity
•little evidence to suggest it is biologically important

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

What are some of the features of Z-DNA?

A

•left handed helix
•12 bp per turn
•may play a role in transcription and chromosome structure

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

What’s the difference between B-DNA and Z-DNA?

A

B-DNA
•bases relatively perpendicular to the central axis

Z-DNA
•bases substantially tilted relative to central axis
•sugar phosphate backbone follows zigzag pattern

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

Can DNA form a triple helix? If so, explain

A

Yes.
Synthetic DNA oligomers were found to complex to double stranded DNA to form a triplex.

Found to occur in nature during instances of recombination and inactivation of specific genes

Potential tool for therapeutic gene inactivation

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

Explain the structure of RNA

A

•RNA strands typically several hundred to thousand nucleotides in length
•Only one of two strands of DNA is used as template in RNA synthesis

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

Explain RNA secondary structure

A

•although usually single stranded, RNA molecules can form short double-stranded regions
•secondary structure due to complementary base pairing (A to U, C to G)
•RNA double helices are typically right handed (11-12 base pairs per turn)

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

What are the 4 RNA secondary structures possible?

A
  1. Bulge Loop ||>
  2. Internal Loop ()
  3. Multibranched Loop +
  4. Stem-loop 💡
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How do viruses self-assemble?

A

Viruses with a simple structure can self-assemble when genetic material and capsid proteins spontaneously bind to each other

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

Explain directed assembly in viruses

A

Complex viruses undergo a process called directed assembly, requiring proteins not part of the virus itself. These noncapsid proteins help with packaging.

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

Explain the bacterial nucleoid

A

Bacterial chromosome is found in the nucleoid, not bounded by membrane so the DNA is direct contact with the cytoplasm

Bacterial chromosomal DNA is usually a circular molecule a few million nucleotides in length

21
Q

Explain the types of genes found in bacterial chromosomes

A
  1. Structural gene sequences (encoding proteins) make up most
  2. Intergenic regions are non transcribed DNA between adjacent genes
22
Q

How do loop domains form in bacterial chromosomal DNA?

A

DNA must be compacted about a 1000-fold in order to fit, causing the formation loop domains

23
Q

What is additional compaction of bacterial chromosomes called?

A

DNA supercooling, where loop domains get even more compact

24
Q

What two main enzymes control supercooling in bacteria

A
  1. DNA gyrase (topoisomerase II)
    •introduced negative supercoils and relaxes positive supercoils
  2. DNA topoisomerase I
    •introduced positive supercoils and relaxes negative supercoils
25
Q

How do eukaryotic genomes vary in size?

A

Difference in size is not because of extra genes. Accumulation of repetitive DNA sequences is what makes the difference

26
Q

What is a nucleosome?

A

Double stranded DNA wrapped around an octamer of four histone proteins (2 copies of each = 8 total)

27
Q

What is the H1 linker histone?

A

It binds to linker DNA and nucleosomes

28
Q

What are the “beads on a string”?

A

Connected nucleosomes resemble beads on a string (seven-fold reduction of DNA length)

29
Q

What is the 30 nm fiber?

A

When nucleosomes associate with each other to form a more compact structure (another 7-fold)

30
Q

How does the third level of compaction in eukaryotic chromosomes work?

A

Third level of compaction involves the interaction between the 30 nm fiber and the nuclear matrix, creating radial loops

31
Q

What are the two parts of the nuclear matrix?

A
  1. Nuclear lamina (fibers that line the inner nuclear membrane)
  2. Internal matrix proteins (connected to nuclear lamina and fills interior of nucleus)
32
Q

Describe euchromatin

A

The less condensed regions of chromosomes
Transcriptionally active
Regions where the 30 nm fibers form radial loop domains

33
Q

Describe heterochromatin

A

Tightly compacted regions of chromosomes
Transcriptionally inactive
Radial loop domains compacted even further

34
Q

What are the two types of heterochromatin?

A
  1. Constitutive heterochromatin
    •regions that are always heterchromatix and permanently inactive with transcription
  2. Facultative heterochromatin
    •regions that can interconvert between euchromatin and heterochromatin
35
Q

What is condensin?

A

•plays a critical role in condensation
•in cytoplasm during interphase
•binds to chromosomes and compacts the radial loops

36
Q

What are cohesins?

A

•plays critical role in sister chromatid alignment
•meet at centromere then degrades

37
Q

What are the three replication models?

A
  1. Conservative model
    •both parental strands stay together after DNA replication
  2. Semiconservative model
    •double-stranded DNA contains one parental and one daughter strand following replication
  3. Dispersive model
    •parental and daughter DNA are interspersed in both strands following replication
38
Q

Where does bacterial DNA replication start?

A

•begins at the origin of replication (bacterial chromosomes only have one)
•DNA synthesis proceeds bidirectionally

39
Q

When does bacterial DNA replication end?

A

When replication forks meet at the opposite end

40
Q

What are the three types of DNA sequences that are functionally significant?

A
  1. AT-rich region
  2. DnaA boxes
  3. GATC methylation sites
41
Q

What does the DNA helicase do?

A

Separates the two DNA strands by breaking down the hydrogen bonds between them

42
Q

What is DNA gyrase’s role in replication?

A

Travels ahead of the helicase and alleviates any supercoils that form

43
Q

What is the role of single stranded binding proteins in replication?

A

Bind to the separated dna strands to keep them apart

44
Q

How are RNA primers synthesized?

A

DNA primase

45
Q

Explain the different DNA polymerases

A

•DNA Pol I: composed of a single polypeptide, removes RNA primers and replaces with DNA
•DNA Pol III: composed of ten subunits, workhorse of replication

46
Q

What is the primosome?

A

When the helicase and primase are bound to each other

47
Q

What is the replisome?

A

The primosome associated with two DNA polymerase

48
Q

How are the leading and lagging strands replicated?

A

DNA pol III act in concert to replicate leading and lagging strands

Bio 184 (5 decks)

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