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

genes

1

What was the chemical structure of a gene?

-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

2

Chromosomes contain

DNA and protein

3

building blocks of DNA

nucleic acids

4

What is DNA made up of

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

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

DNA has polynucleotide chains with nucleotide

6

what is a nucleotide?

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

7

What is the sugar in DNA?

deoxyribose

8

What are the 4 bases?

adenine, cytosine, guanine, and thymine

9

What is the 3D structure of DNA?

double helix, 1 turn every 10 bp

10

each strand's sequence is complementary to partner

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

11

Whare are the purines?

adenine and guanine

12

What are pyrimidines?

cytosine and thymine

13

What does adenine pair with?

thymine... 2 hydrogen bonds

14

What does guanine pair with?

cytosine (3 hydrogen bonds)

15

complete set of information in a an organims's DNA

genome

16

At replication, the entire genome must be

duplicated and passed to the daughter cell

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allow for the genome to be replicated

complimentary strands, each strand serves as the template

18

Dna has Minor and major groves

....

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

chromosome

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autosomes and sex chromsomes

22 pairs and 2 sex

21

Each chromosome is a

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

22

What information is found on chromosomes?

encoding proteins
encoding RNA molecules

23

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

regulatory information
"Junk" DNA

24

2 copies are called

homologs

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Little of genome is

protein coding

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most DNA is

transposable elements
lots of intonic sequences
regulatory sequences

27

region of gene that codes for proteins

exons

28

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

coding regions (exons)

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sequences are relatively conserved during evolution

functional

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sequences mutate randomly wo consequnces

non functional

31

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

them are conserved in the same order on the chromosome "conserved synteny"

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

interphase

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become highly condensed and separated into two duaghter nuclei

mitosis

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where duplication of the DNA begins

DNA replication origin

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

centromere

36

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

telomere

37

must allow rapid localized access to DNA for gene expression

dynamic situation

38

DNA binding protines involved in forming chromosomes

histones and non-histone chromosomal proteins

39

Protein + nuclear DNA=

chromatin

40

most basic unit of chromosome packing

nucleosome

41

beads on a string

linker DNA and DNA wrapped around histones

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nucleosome is made up of

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

43

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

nucleases

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small proteins with common structural motif called histone fold

histones

45

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

Covalent modifications important for chromatin regulation

46

interactions btw DNA and histone

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

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

salt linkages

48

Chromatin remodeling complexes

allow further loosening of DNA/ histone contact

49

proteins are related to....

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

50

stacking may be facilited by histone tails (esp H4)
H1 "linker histone" is present in 1:1 ratio with nucleosome cores

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

51

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

Histone H1