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Principles of Disease > Storing and Using Genetic Information > Flashcards

Flashcards in Storing and Using Genetic Information Deck (28):
1

Phenotype

outward, physical manifestation of organism

2

Genotype

full hereditary information of an organism

3

What is a nucleotide composed of?

-sugar
-base
-phosphate group

4

What sugar is found in DNA?

2'-deoxyribose

5

Describe the curve of the double helix.

-Contains major and minor curves which provide stability
-Right-handed- spirals clockwise

6

What are the complementary base pairs?

-adenine and thymine (uracil in RNA)
-cytosine and guanine

7

Describe the structure of the nucleus

-largest organelle (usually)
-contains cells genetic material
-site of DNA replication and decoding

8

What are chromosomes?

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

9

What is chromatin?

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

10

What is the difference between heterochromatin and euchromatin?

-Heterochromatin= condensed and silenced
-euchromatin= extended and expressed

11

What do transcription and replication both require?

Two strands of DNA to separate temporarily to allow enzymes access to the DNA template

12

What possess barriers to enzymes?

nucleosomes and folding of chromatin

13

What are the 2 major mechanisms by which chromatin is made more accessible?

-histones can be enzymatically modified
-histones can be displaced by chromatin remodelling complexes
-both processes are reversible

14

Semi-conservative

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

15

In what direction does DNA replication take place?

5' to 3'

16

Where are Okazaki fragments formed

on the lagging strand

17

What does telomerase do?

replicates the 5' end of the lagging strand

18

Exon

Coding region of DNA

19

Intron

non-coding region of DNA

20

Degeneracy

All of the amino acids (exc methionine and tryptophan) are encoded by more thatn 1 codon.

21

What is the mutation behind SCA?

single point mutation where hydrophilic glutamate is substituted to hydrophobic valine

22

What is mRNA?

-transcribed from DNA
-carries information for protein synthesis

23

What is the major role of RNA?

to participate in protein synthesis

24

Alternative Splicing

a process by which exons of the RNA produced by transcription are reconnected in multiple ways during RNA splicing

25

What determine the reading frame of RNA sequence

initiation codon

26

What is the major role of tRNA?

to translate mRNA into amino acid sequence and acts as an adapter molecule between the coded amino acid and the mRNA

27

Describe rRNA?

-component of ribosomes
-rRNA molecules are produced in the nucleus
-transported to cytoplasm, where they combine with proteins to form a ribosome

28

What is a polysome

when several ribosomes translate mRNA at one time