Mr P bio 7 Nucleic Acids

Question 1

what are the 3 components of a nucleotide?

Answer 1

phosphate group, organic base and pentose sugar

Question 2

what does DNA stand for?

Answer 2

Deoxyribonucleic acid

Question 3

what is the monomer of DNA?

Answer 3

nucleotide

Question 4

what are the 3 components of DNA?

Answer 4

phosphate group, organic base and deoxyribose sugar

Question 5

what is the structure of DNA?

Answer 5

double helix consisting of 2 polynucleotide strands held together by hydrogen bonds between the paired bases

Question 6

which bases pair with which in DNA?

Answer 6

Adenine with thymine
guanine with cytosine

Question 7

how many hydrogen bonds does each base pair form?

Answer 7

A-T= 2
G-C=3

Question 8

what are the two bonds found within DNA?

Answer 8

hydrogen and phophodiester

Question 9

where are phosphodiester bonds found?

Answer 9

between the sugar and phosphate group

Question 10

how are DNA strands formatted?

Answer 10

they are antiparallel

Question 11

how is DNA adapted for its function as a storage molecule? (6)

Answer 11

-DNA has a sugar-phosphate backbone
-DNA is a really large molecule so can store lots of info
-DNA is coiled into a helix so is compact
-base sequence codes for amino acids/ proteins
-DNA is double stranded (covered later on in year)
-DNA has many weak H bonds for replication

Question 12

why is DNA’s sugar phosphate backbone an adaptation for its function as a storage molecule?

Answer 12

when coiled into a double helix, this provides strength and stability and protects the bases from damage

Question 13

What are the 3 components of RNA?

Answer 13

Phosphate group, nitrogenous base, ribose sugar

Question 14

What are the 3 types of RNA?

Answer 14

Messenger, transfer and ribosomal

Question 15

What are the differences between DNA and RNA?

Answer 15

RNA-single stranded, uses uracil, 1 polynucleotide chain, uses ribose sugar, several 100s-1000s of nucleotides in a chain
DNA-double stranded, uses thymine, 2 polynucleotide chains, uses deoxyribose’s sugars, many millions of nucleotides in a chain

Question 16

What is the structure of mRNA?

Answer 16

Single stranded polynucleotide chain that is a copy of a single gene on the DNA so length depends on no of bases in gene so shorter than DNA

Question 17

WhT does mRNA have instead of thymine?

Answer 17

Uracil

Question 18

how is the structure mRNA related to the structure DNA?

Answer 18

it is complementary

Question 19

what is the sequence of 3 bases called?

Answer 19

codon

Question 20

how many amino acids does each codon code for?

Answer 20

one

Question 21

approximately, how many nucleotides are contained in tRNA’s polynucleotide chain?

Answer 21

75

Question 22

how many polynucleotide chains does tRNA contain?

Answer 22

1

Question 23

what is the structure of tRNA compared to?

Answer 23

clover leaf

Question 24

what are the different components of tRNA?

Answer 24

amino acid attachment site, sugar phosphate backbone, anticodon

Question 25

within tRNA, what bonds join the complementary bases?

Answer 25

hydrogen

Question 26

what is the role tRNA?

Answer 26

to carry a specific amino acid to the site of protein synthesis and its anticodon base-pairs with the codon on the mRNA molecule

Question 27

what are the differences between DNA and tRNA?

Answer 27

DNA-deoxyribose, thyomine, 2 polynucleotide strands, many millions of nucleotides in chain tRNA- ribose, Uracil, 1 polynucleotide strand, about 75 nucleotides in a chain

Question 28

what are the components of ATP?

Answer 28

nitrogenous organic base and 3 phosphate groups

Question 29

what is ATP formed from?

Answer 29

from ADP and inorganic phosphate

Question 30

what reaction occurs to form ATP and what bond is formed?

Answer 30

condensation reaction and requires lots of energy to add a phosphate group to ADP so a high energy covalent bonds is created

Question 31

what enzyme formed ATP?

Answer 31

ATP synthase

Question 32

what happens when ATP is hydrolysed?

Answer 32

easily broken down back into ADP and inorganic phosphate and when this happens the bond between the 2nd and 3rd phosphate breaks and releases large amounts of usable energy

Question 33

why is ATP useful?

Answer 33

1. energy released in small amounts 2. ATP is soluble 3. involves a single reaction

Question 34

what are 3 uses of ATP?

Answer 34

active transport, muscle contraction and protein synthesis

Question 35

which enzyme speeds up the hydrolysis of ATP?

Answer 35

ATP hydrolase

Question 36

what is a gene?

Answer 36

a section of DNA that codes for a particular polypeptide and can also code for a functional RNA

Question 37

what is the location of a gene on a particular DNA molecule called?

Answer 37

locus

Question 38

what is the genome?

Answer 38

all of an organisms genes

Question 39

what is the name for the range of proteins that a cell produces using its DNA?

Answer 39

proteome

Question 40

what is an allele?

Answer 40

different forms of the same gene

Question 41

why is the genetic code described as being universal?

Answer 41

triplet codes code for the same amino acids in all organisms

Question 42

why is the genetic code described as being non- overlapping?

Answer 42

the ribosome reads each base only only once in the codons

Question 43

why is the genetic code described as being degenerate?

Answer 43

more than one triplet codes for an amino acid

Question 44

how does a change in the base sequence of DNA lead to an enzyme not functioning? (4)

Answer 44

-DNA base sequence codes for sequence of amino acids/ primary structure -changing the H, ionic and disulphide bonds between R groups -change in tertiary structure and shape of active site -substrate unable to bind so no enzyme- substrate complexes formed

Question 45

how is the DNA in a prokaryotic cell different to in a eukaryotic cell?

Answer 45

prokaryotes contain a single circular DNA molecule and often contain one or more plasmids whereas eukaryotic cells contain chromosomes

Question 46

what is a chromosome?

Answer 46

linear DNA molecule wrapped around a protein called a histone to form a rod like structure

Question 47

where is non-coding DNA found?

Answer 47

in between genes

Question 48

what is a non-coding repeat?

Answer 48

a sequence of bases which is repeated a number of times

Question 49

what is non-coding DNA within a gene called?

Answer 49

intron

Question 50

list the 5 differences between prokaryotic and eukaryotic DNA

Answer 50

prokaryotic- stored in one long, circular DNA ring, smaller, no associated proteins, doesn't form chromosomes, no non- coding DNA in plasmid eukaryotic- linear DNA, larger, associated with proteins called histones, forms chromosomes, contains introns and non-coding repeats

Question 51

give 2 ways in which the hydrolysis of ATP is used in cells

Answer 51

processes such as active transport to add phosphate to other substances and make them more reactive

Question 52

describe how ATP is resynthesised in cells

Answer 52

ATP synthase is used to change ATP and phosphate to ATP during respiration/ photosynthesis

Question 53

explain how the organic bases help to stabilise the structure of DNA

Answer 53

hydrogen bonds between base pairs holds 2 strands together and many hydrogen bonds provide strength

Question 54

explain how humans and grasshoppers can have a similar percentage of each base in their DNA

Answer 54

they have different genes so triplets are in a different order so different amino acid sequence coded for

Question 55

Give three ways in which the DNA in a chloroplast is different from DNA in the nucleus.

Answer 55

In Chloroplasts: -DNA shorter -fewer genes -circular -not associated with proteins -introns absent