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0
Q

What was the chemical structure of a gene?

A
  • passed from cell to daughter cell mostly unchanged
  • undergoes accurate and unlimited replication
  • must direct development of a cell and the daily life of the cell
1
Q

the information- containing elements that determine the characteristics of a species

A

genes

2
Q

Chromosomes contain

A

DNA and protein

3
Q

building blocks of DNA

A

nucleic acids

4
Q

What is DNA made up of

A
polynucleotides have POLARITY
5' phosphoryl end
3' hydroxyl end
phasphate group, sugar group and a base... hooked together by hydroxly polariy linkage.
always 5-3 prime
5
Q

What has 2 long …. with 4 types of …. subunits

A

DNA has polynucleotide chains with nucleotide

6
Q

what is a nucleotide?

A

5-carbon sugar and nitrogenous base covalently linked via glycosidic bonds

7
Q

What is the sugar in DNA?

A

deoxyribose

8
Q

What are the 4 bases?

A

adenine, cytosine, guanine, and thymine

9
Q

What is the 3D structure of DNA?

A

double helix, 1 turn every 10 bp

10
Q

each strand’s sequence is complementary to partner

A

antiparallel, helps DNA function the way it does.. allows for replication

11
Q

Whare are the purines?

A

adenine and guanine

12
Q

What are pyrimidines?

A

cytosine and thymine

13
Q

What does adenine pair with?

A

thymine… 2 hydrogen bonds

14
Q

What does guanine pair with?

A

cytosine (3 hydrogen bonds)

15
Q

complete set of information in a an organims’s DNA

A

genome

16
Q

At replication, the entire genome must be

A

duplicated and passed to the daughter cell

17
Q

allow for the genome to be replicated

A

complimentary strands, each strand serves as the template

18
Q

Dna has Minor and major groves

A

….

19
Q

single long linear DNA molecular associated with proteins that fold and pack it into compact structre

A

chromosome

20
Q

autosomes and sex chromsomes

A

22 pairs and 2 sex

21
Q

Each chromosome is a

A

single long linear DNA molecular associated with protiens that fold and pack it into compact structure

22
Q

What information is found on chromosomes?

A

encoding proteins

encoding RNA molecules

23
Q

Information that does not contain DNA in a chromosomes is for?

A

regulatory information

“Junk” DNA

24
Q

2 copies are called

A

homologs

25
Q

Little of genome is

A

protein coding

26
Q

most DNA is

A

transposable elements
lots of intonic sequences
regulatory sequences

27
Q

region of gene that codes for proteins

A

exons

28
Q

typically 145 bp floating in sea of lg introns, the sequence of which is of little consequence

A

coding regions (exons)

29
Q

sequences are relatively conserved during evolution

A

functional

30
Q

sequences mutate randomly wo consequnces

A

non functional

31
Q

not only do we share the same genes, but large blocks of

A

them are conserved in the same order on the chromosome “conserved synteny”

32
Q

chomosomes are replicated; they are decondensed and ccant be easily distinguished

A

interphase

33
Q

become highly condensed and separated into two duaghter nuclei

A

mitosis

34
Q

where duplication of the DNA begins

A

DNA replication origin

35
Q

allows one copy of each duplicated and condensed chromosmes to be pulled into each daughter cell when the cell divides

A

centromere

36
Q

at the end of a chromsomes, contain repetitive sequences that enable the end to be efficiently replicated

A

telomere

37
Q

must allow rapid localized access to DNA for gene expression

A

dynamic situation

38
Q

DNA binding protines involved in forming chromosomes

A

histones and non-histone chromosomal proteins

39
Q

Protein + nuclear DNA=

A

chromatin

40
Q

most basic unit of chromosome packing

A

nucleosome

41
Q

beads on a string

A

linker DNA and DNA wrapped around histones

42
Q

nucleosome is made up of

A

histone octomer
8 histone protiens
-2 molecules each of H2A, H2B, H3, H4
- And 2x stranded DNA that is 147 nucleotide pairs long

43
Q

what break down DNA by cutting btw nucleosomes and degrading the exposed DNA btw nucelosome core particles?

A

nucleases

44
Q

small proteins with common structural motif called histone fold

A

histones

45
Q

What are N terminal amino acid tail that extends out from the core of nucleosome improtant for?

A

Covalent modifications important for chromatin regulation

46
Q

interactions btw DNA and histone

A

142 H bonds are formed btw DNA and histone core in each nucleosome
Hydrophobic interactions
salt linkages
histones are highly conserved; most changes would be lethal
specialized variant histone proteins add to vaious possiblechromatin sturctures

47
Q

lysine and arginine (positive charges) comprise more than 1/5 of histone residues; effectively neutralize negatively charged DNA backbone

A

salt linkages

48
Q

Chromatin remodeling complexes

A

allow further loosening of DNA/ histone contact

49
Q

proteins are related to….

A

helicases and are ATP dependent; bind to both protein core and DNA

50
Q

stacking may be facilited by histone tails (esp H4)

H1 “linker histone” is present in 1:1 ratio with nucleosome cores

A

zig zag model… nucleosome packing- a dense fibrous structure w diameter of 30 nm

51
Q

linker histone
larger than other histone proteins- also less well conserved
contacts both DNA and protein
changes the path of the DNA as it exits the nucleosome

A

Histone H1