storing and using genetic information Flashcards Preview

PRINCIPLES OF FUN > storing and using genetic information > Flashcards

Flashcards in storing and using genetic information Deck (38):
1

what is a phenotype?

outward physical manifestation of organism

2

what is a genotype?

full genetic code of organism (even if not expressed)
entire DNA content

3

what determines protein function?

protein structure

4

what are the four different bases in DNA?

A
T
G
C

5

what sugar is used in DNA monomers?

2-deoxyribose

6

what is the difference between 2-deoxyribose and ribose sugars?

in ribose sugar there is an OH group on the 2' carbon as opposed to an H in 2-deoxyribose

7

what direction do the polynucleotide chains run in in relation to each other?

anti parallel

8

what bases bind to each other?

A - T (or uracil in RNA)
C-G

9

where does replication of DNA and the first steps in decoding it for protein production take place?

nucleus

10

what is the DNA molecule packaged into in the nucleus?

chromosomes

11

what is a chromosome?

single piece of DNA containing many genes, regulatory elements and other nucleotide sequences

12

what is DNA wrapped around in order to shorter its length?

histones

13

what is chromatin?

mixture of DNA, proteins and RNA that package DNA within the nucleus

14

what are the two forms of chromatin?

heterochromatin (inactive)
euchromatin (active)

15

why does banding occur in chromosome?

due to different densities of packaged DNA

16

why does the cell have to copy its DNA completely in order to divide?

so that both daughter cells have a full set of chromosomes

17

why does the DNA helix have to separate before it can be replicated?

to allow enzymes access to the DNA template

18

what are the two major mechanisms by which chromatin is made more accessible?

histones can be enzymatically modified
histones can be displaced by chromatin remodeling complexes

19

what is semi conservative copying?

one half of each new DNA molecule is new and one is old

20

what is bi-directional replication?

replication in 2 directions

21

what direction is DNA replicated in?

5' end to 3' end

22

how much of the human genome codes for proteins?

less than 2%

23

what are introns?

non coding regions

24

what are exons?

coding regions

25

what is a codon?

set of 3 bases

26

what does each codon specify?

a particular amino acid

27

how many codons are there?

64

28

how many amino acids are found in proteins?

20

29

whar is the initiation codon?

methionine

30

what mutation occurs in sickle cell anaemia?

glutamate is substituted for valine, (GAA or GAG becomes GUA or GUG)

31

what is the role of RNA?

participate in protein synthesis

32

what does mRNA carry?

information for protein synthesis

33

what is alternative splicing?

process by which the exons of RNA produced by transcription of a gene are reconnected in multiple ways - means one gene can code for multiple proteins

34

what is the purpose of a stop codon?

prevents the wrong protein being synthesised

35

what is the open reading frame?

set of codons that run continuously and are bounded by a start/initiation codon and a termination codon

36

what is the role of tRNA?

translate mRNA sequence into amino acid sequence - brings proteins to ribosomes

37

what does rRNA do?

combines with proteins to form a ribosome

38

what is a polysome?

several ribosomes translating mRNA at one time.