Topic 1.3 Biological molecules 2

Question 1

What are nucleotides?

Answer 1

molecules with 3 parts, a 5-carbon pentose sugar, nitrogen-containing base and a phosphate group (joined by condensation reactions)

Question 2

What is ATP, adenosine triphosphate?

Answer 2

a nucleotide that acts as the universal energy supply molecule in cells. it is made up of an adenosine base, pentose sugar ribose and 3 phosphate groups

Question 3

What are purine bases?

Answer 3

bases found in nucleotides which have 2 nitrogen-containing rings

Question 4

What are pyrimidine bases?

Answer 4

bases found in nucleotides which has 1 nitrogen-containing ring

Question 5

What is adenine and guanine?

Answer 5

purine bases found in DNA and RNA

Question 6

What is cystosine?

Answer 6

pyrimidine base found in DNA and RNA

Question 7

What is thymine?

Answer 7

pyrimidine base found in DNA

Question 8

What is uracil?

Answer 8

pyrimidine base found in RNA, replaces thymine

Question 9

What is the function of ATPase?

Answer 9

an enzyme that catalyses the formation and breakdown of ATP, depending on conditions

Question 10

What is ADP, adenosine diphosphate?

Answer 10

a nucleotide formed when ATP loses a phosphate group and provides energy to drive reactions in the cell

Question 11

Define redox reactions

Answer 11

reactions in which one reactant loses electrons

oxidation) and another gains electrons (reduction

Question 12

Define nucleic acids

Answer 12

polymers made up of many nucleotide monomer units that carry all the information needed to form new cells

Question 13

What is a phosphodiester bond?

Answer 13

the bond formed between the phosphate group of one nucleotide and the sugar of the next nucleotide in a condensation reaction. DNA ligase catalyses their formation in DNA replication

Question 14

Define a genome?

Answer 14

the entire genetic material of a organism

Question 15

Which base does adenine pair with?

Answer 15

A,T thymine

Question 16

Which base does guanine pair with?

Answer 16

C,G cytosine

Question 17

What bond forms between 2 strands of DNA to form the double helix structure?

Answer 17

hydrogen bonds

Question 18

How many hydrogen bonds are between C and G?

Answer 18

3 bonds

Question 19

How many hydrogen bonds are between A and T?

Answer 19

2 bonds

Question 20

What are the names are the 2 strands?

Answer 20

5’ and 3’ according to which carbon the phosphate group is attached to in the first nucleotide of the chain

Question 21

How does DNA replicate?

Answer 21

copies itself exactly

Question 22

How was DNA replication tested?

Answer 22

though experiments on semi-conservative and conservative replication

Question 23

What is conservative replication?

Answer 23

where the double helix remains intact and new stands form on the outside

Question 24

What is semiconservative repliaction?

Answer 24

where the double helix unzips and each strand replicates to produce a second, new strand

Question 25

What does DNA helicase do?

Answer 25

an enzyme involved in DNA replication that unzips two strands on the DNA molecule

Question 26

What does DNA polymerase do?

Answer 26

an enzyme involved in DNA replication that lines up and catalyses the linking up of the nucleotides along the template strand

Question 27

What is the function of DNA ligase?

Answer 27

an enzyme involved in DNA replication that catalyses the formation of phosphodiester bonds between the 2 strands of DNA

Question 28

Describe translation

Answer 28

the process by which proteins are produced, via RNA, using the genetic code found in the DNA. takes place on the ribosomes

Question 29

What are ribosomes?

Answer 29

the site of protein synthesis in the cell

Question 30

Define the triplet code

Answer 30

the code of 3 bases and is the basis of the genetic information in DNA

Question 31

What is a gene?

Answer 31

a sequence of bases on a DNA molecule. contains coding for a sequence of amino acids in a polypeptide chain that affect a characteristic in the phenotype of the organism

Question 32

Define a codon

Answer 32

a sequence of 3 bases in DNA or mRNA

Question 33

What's a complementary strand?

Answer 33

the strand of RNA formed that complements the DNA acting as the coding strand

Question 34

What type of mutation causes sickle cell disease?

Answer 34

substitution

Question 35

What is an anticodon?

Answer 35

a sequence of 3 bases on tRNA that are complementary to the mRNA codon

Question 36

What is a mutagen and examples?

Answer 36

anything that increases the rate of a mutation e.g. smoking, x-rays

Question 37

Explain the importance of DNA replication during the development of a zygote into a blastocyst

Answer 37

- zygote divided several times by mitosis - to make identical copies of the DNA/chromatids - so that all the cells will be diploid - so that when the mitochondria divide they will have a copy of the DNA