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Flashcards in Nucleic Acids Deck (28)
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1

What does DNA stand for

Deoxyribosenucleic acid

2

Describe the structure of a nucleotide

Pentose sugar (deoxyribose in DNA)

A phosphate group attached to the sugar

A nitrogenous base (A,T,C or G)

3

What is the difference between ATP and a RNA nucleotide

ATP has become phophorylated (gained 2 extra phosphates)

4

What term describes the direction the 2 DNA strands run in

Antiparallel

5

What is the name of the covalent bond between the pentose sugar and the phosphate

Phosphodiester bond

6

What is a purine and what are the 2 examples

A purine is a nitrogenous base with 2 rings

Adenine and Guanine

7

What is a pyramidine and what are the 2 examples

A pyramidine is a nitrogenous base with only 1 ring

Thymine and Cytosine

8

How many hydrogen bonds form between A and T

2

9

How many hydrogen bonds form between C and G

3

10

What is the name of the shape of a DNA molecule

Double Helix

11

How is DNA stored in Eukaryotes

The majority is stored in the nucleus

wrapped around protiens called histones to form chromosomes

there is a loop of DNA without a histone in mitochondria and chloroplasts

12

How is DNA stored in Prokaryotes

DNA is in a loop within the Cytoplasm (no nucleus)

DNA is described as naked as it has no histone

13

What stage of the cell cycle does DNA replication take place

Interphase
(S)

14

What is the name of the enzyme that catalyses the 'unzipping' process

DNA Helicase

15

What enzyme catalyses the unwinding process

Gyrase

16

What is the name of the type of replication DNA performes

Semi-conservative Replication

17

What is Semi-conservative Replication

DNA replication where 1 strand in the new molecule is from the origional molecule and 1 strand is newly formed

18

What is the name for a different variation of a gene

an Allele

19

What are the 5 structural differences between RNA and DNA

Sugar is different (Ribose in RNA)

Uracil replaces Thymine

Single stranded

Shorter chain

3 forms of RNA (mRNA, tRNA and rRNA)

20

What specifically does DNA code for

the Amino acid sequence (primary structure)

21

Why is it importand that the amino acid sequence (primary structure) is correct

because then it allows the chain to flod and be held in its tertiary structure giving it its specific 3D shape

Having a specific 3D shape is vital to a protiens function

22

What process allows the genetic code to be able to be moved out the nucleus, and what molecule does this form

Transcription

forms mRNA

23

Describe the process of Transcription

Gyrase and DNA helicase unwind and unzip the DNA

Hydrogen bonds break between bases

RNA polymerase catalyses the formation of tempory hydrogen bonds between RNA nucleotides and the DNA bases

The RNA strand is now complementary to the 'template strand'

mRNA moves out the nucleus and joins a ribosome

24

Where are tRNA molecules made

the Nucleolus

25

What is the name of the 3 bases at the top of the loop on a tRNA molecule

the Anticodon

26

What joins to the 3 bases at the straight tip of a tRNA molecule

Amino acid

27

What causes the ribosome to stop moving along the mRNA chain

the Stop Codon

28

What happens to the mRNA chain after translation

it breaks down into free nucleotides again