Brainscape's Knowledge GenomeTM

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


See full index

mbb 201 > lecture 9 > Flashcards

lecture 9 Flashcards

1
Q

if two daughter cells do not divide properly

A

you will have a piece of chromosome added onto another chromosome

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

how do we know that DNA carries genetic info?

A

Griffith experiment (1920s)

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

What did Griffith’s experiment find?

A

two strains of S. Pneumoniae
1. one is lethal (S strain)
2. one is harmless (R strain)

Heat-killed S strain does not kill mice

Mixing heat-killed red with yellow kills mice even though the red strain is dead!

CONCLUSION: transformation!!!!
the ability of the unknown factor to “transform” the harmless strain into a harmful one

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

Avery, MacLeod and McCarthy experiment (1944)

A

isolated individual components from the S strain cells and tested their ability to transform the R strain

conclusion: the molecule that contains the heritable info is DNA

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

Hershey and Chase (1952)

A

conclusion:
DNA enters bacteria and carries the genetic information

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

primary DNA structure

A

the nucleotide sequence

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

secondary DNA structure

A

any regular, stable structure taken up by some or all of the nucleotides

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

tertiary DNA structure

A

complex 3D folding of nucleic acids
(ex. into eukaryotic chromatin and bacterial nucleoids)

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

Nucleoside

A

base + sugar (ex. adenosine)

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

Nucleotide

A

base + sugar + phosphate (ex. adenosine monophosphate AMP)

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

phosphate linkages

A

5’ phosphate of one nucleotide unit is joined to the 3’ hydroxyl group of the next nucleotide, creating a PHOSPHODIESTER linkage

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

nucleotide net charge

A

negative

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

From Purines: you can make

A

Adenine and Guanine
(depending on the substrate)

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

From Pyrimidines: you can make

A

Cytosine, Thymine, and Uracil

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

pentose forms a covalent bond with the base called a

A

beta-glycosidic linkage
(bonds joining a sugar to another group)

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

DNA secondary structure: the double helix

A

the two strands of DNA are wound around the same axis to form a right-handed double helix

the strands run in opposite directions (anti-parallel, one 3’ to 5’ and the other 5’ to 3’)

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

Two DNA strands interact via

A

base pairing (H bonding) through complementary bases

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

Complementary bases in the double helix

A

-Adenine forms two H bonds w thymine (or uracil)
-Guanine forms three H bonds w cytosine

A=T (or A=U) and G≡C base pairs predominate in double stranded DNA and RNA

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

base stacking: which interactions?

A

van der waals interactions and some dipole-dipole interactions

bases are not directly ontop of eachother

20
Q

base stacking between the hydrophobic bases minimizes their

A

contact with water and is very important for stabilizing the double helix

21
Q

your DNA is highly — charged

A

negatively

22
Q

DNA structure (shape, xray)

A

DNA produces an Xray diffraction pattern: discovered by Rosalind Franklin

DNA molecules are helical with two periodicities (regular repeating patterns)

23
Q

DNA secondary structure: watson-crick base pairing

A

watson and crick determined the double helix structure of DNA

24
Q

The specific pairing of bases (G≡C, A=T) permits the

A

duplication of genetic information

25
Q

Chargaff’s rule

A

A=T and G=C
A+G = T+C

26
Q

You have isolated the DNA from 2 species of bacteria. Thymine accounts for 10% of the bases in the first and 25% in the second species.

What is the relative proportion of adenine, guanine, and cytosine for the two species? (chargaff’s rule)

A

species 1:
T 10%, A 10%, G 40%, C 40%

species 2:
T 25%, A 25%, G 25%, C 25%

27
Q

Watson-Crick (WP) paper published in 1953

A

DNA will be duplicated by opening the double stranded helix and using one of the strands to copy the info from

(nobel prize given to them from this! most cited paper ever?!)

28
Q

DNA grooves

A

DNA contains two grooves where the bases are exposed known as the major groove and minor grooves

They are common locations for protein-DNA interactions

29
Q

the alpha helix fits in the — perfectly!

A

major groove

30
Q

Chromatin

A

complex of DNA and protein

31
Q

Chromosomes

A

Chromatin in a compacted form

32
Q

Why is compaction (or chromatin) necessary in chromosomes?
how much is DNA compacted?

A

each human cell contains 2m DNA packaged into a cell that is 5-8 micrometers in diameter.

DNA is compacted about 10,000 fold

33
Q

Karyotype

A

an ordered display of the full set of chromosomes

34
Q

Human chromosome characteristics

A

humans have 46 chromosomes, most are a homologous pair (one maternal, one paternal)

-can be used to detect genetic defects

35
Q

Genome

A

the total genetic information carried by all the chromosomes in a cell

36
Q

a lot of the DNA in our genome is called

A

junk DNA!
because its function is unknown

37
Q

Is there a simple relationship between gene number, chromosome number, and total genome size?

A

no!

38
Q

what are the two broad phases of the cell cycle?

A

Interphase and Mitosis

39
Q

Interphase

A

when chromosomes are duplicated

-interphase chromosomes are extended and hard to see using a light microscope

40
Q

Mitosis

A

when chromosomes are segregated to two daughter molecules

-mitotic chromosomes are extremely compact and easy to visualize

41
Q

telomeres

A

repeated sequences at the ends of chromosomes. protects from degradation

42
Q

if we did not have telomeres, what would happen to the chromosome?

A

each time replication occurred, the chromosome would shorten

43
Q

Replication origin

A

sequence where replication begins

44
Q

centromere

A

sequence that allows DNA to be separated during M phase. region of attachment to mitotic spindle

45
Q

based on what you know about hydrogen bonding, what kind of nucleotides would you expect to be common at the replication origin?

A

A and T because it is easier to open (weaker H bond)

46
Q

Interphase chromosomes: distribution

A
  • NOT randomly distributed in the nucleus
  • each chromosome occupies a specific region
  • chromosomes may be attached to the nuclear envelope or to the protein meshwork that supports it
47
Q

nuclear lamina

A

the protein meshwork that supports the chromosomes

mbb 201 (24 decks)

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