More biological molecules

Question 1

What does DNA stand for?

Answer 1

deoxyribonucleic acid

Question 2

What does RNA stand for?

Answer 2

ribonucleic acid

Question 3

What is the structure of a nucleotide?

Answer 3

pentose sugar, phosphate group and a nitrogenous base

Question 4

What bond forms when nucleotides are joined together?

Answer 4

-Phosphodiester bond
-Ester bonds

Question 5

Describe the structure of DNA

Answer 5

-Double helix
-Adenine and thymine, cytosine and guanine complementary
-H bonds between bases
-Antiparallel strands
-Sugar-phosphate backbone

Question 6

What are the differences between RNA and DNA?

Answer 6

RNA:
-Ribose sugar
-Uracil, not thymine
-Single polynucleotide strand, not double
-Much shorter than DNA

Question 7

Describe the process of semi-conservative replication

Answer 7

-DNA helicase unwinds and unzips the DNA, by breaking H bonds between bases
-Single strands act as a template, free nucleotides lined up and attached to CBP
-DNA polymerase catalyses the reaction joining nucleotides to template strand
-Each new DNA molecule contains one original strand and one new strand

Question 8

What direction does DNA polymerase move in?

Answer 8

-3’ to 5’ direction

Question 9

What does ATP stand for?

Answer 9

-Adenosine triphosphate

Question 10

What did Meselson and Stahl’s experiment prove?

Answer 10

-Semi-conservative replication

Question 11

What does ATP consist of?

Answer 11

-Adenine
-Ribose
-3 phosphate groups

Question 12

What reaction does ATP hydrolase catalyse?

Answer 12

-The breakdown of ATP

Question 13

What does ATP synthase catalyse?

Answer 13

-The synthesis of ATP

Question 14

What are the 5 importances of water?

Answer 14

-It is a metabolite
-It is a solvent
-High latent heat of vaporisation
-High specific heat capacity
-Cohesive

Question 15

Describe the structure of water

Answer 15

-H20
-H slightly positive, O slightly negative
-Polar molecule
-Hydrogen bonding

Question 16

Why is water being a metabolite important?

Answer 16

-All hydrolysis and condensation reactions are metabolic reactions
-Energy from ATP is released during a hydrolysis reaction

Question 17

Why is water being a good solvent important?

Answer 17

-One side of molecule is negative and one side is negative
-Ions will be entirely surrounded by water, so they will dissolve
-Useful substances can be taken up and dissolved in water and transported around the body

Question 18

Why is water having a high latent heat of vaporisation important?

Answer 18

-Water requires a lot of energy to be turned from a liquid into a gas
-Can be used to cool organisms down without losing too much water

Question 19

Why is water having a high specific heat capacity impoprtant?

Answer 19

-When water is heated, most of the energy is used to break the hydrogen bonds, so temperature doesn’t raise quickly
-Makes water a good habitat as temperature doesn’t experience rapid changes
-Helps organisms maintain a constant internal body temperature

Question 20

Why is water being cohesive important?

Answer 20

-Good for transporting substances
-Water travelling up xylem
-High surface tension
-Allows sweat droplets to form

Question 21

What is a cation?

Answer 21

-Ion with a positive charge

Question 22

What is an anion?

Answer 22

-Ion with a negative charge

Question 23

Why are iron ions important?

Answer 23

-In haemoglobin
-Oxygen binds to them

Question 24

Why are hydrogen ions important?

Answer 24

-Control blood pH
-Affect enzyme-controlled reactions

Question 25

Why are sodium ions important?

Answer 25

-Co-transport with glucose and amino acids

Question 26

Why are phosphate ions important?

Answer 26

-In DNA, RNA and ATP