Properties of Proteins

Question 1

What do proteins determine

Answer 1

• nature of species
• colour of hair, eyes, skin, etc
• whether a cell is muscle, nerve, epithelial or any other

Question 2

What does each protein consist of

Answer 2

A unique sequence of amino acids and a unique 3D shape

Question 3

When is the role of proteins important

Answer 3

information coded into the molecular structure of DNA.

Question 4

How are proteins different from other molecules

Answer 4

They can bind organic molecules and ions selectively

Question 5

What is a ligand

Answer 5

Any molecule or ion that is bound to the surface of another molecule (protein) by forces other than covalent bonding. e.g. electric attraction

Question 6

How does a ligand work

Answer 6

It binds to specific chemical groups on a small area of the protein surface (binding site). Protein binding depends very much on shape - chemical specificity.

Question 7

What are the functions of protein binding sites

Answer 7

• Holding cells together
• Catalysing the chemical reactions in cells (enzymes)
• Communication between different systems of the body (e.g. hormones)

Question 8

What is a gene

Answer 8

The portion of DNA that contains the information required for transmission

Question 9

What is a function of DNA

Answer 9

The transmission of hereditary information from cell to cell. Contains instructions for the synthesis of proteins coded into its molecular structure.

Question 10

Describe the characteristics of DNA

Answer 10

• 2 polynucleotide chains coiled around each other to form a double helix
• 1 molecule of DNA contains the genetic information corresponding to many different proteins arranged as a sequence of genes
• most of a cell’s DNA is in the nucleus

Question 11

How is genetic information transferred to protein?

Answer 11

1) Code carried from DNA to the ribosome in the cytoplasm by RNA
2) Transfer RNA binds & escorts specific amino acids to the ribosome to place each in the correct order dictated by the triplet sequence in messenger RNA
DNA –> RNA –> PROTEIN

Question 12

How is genetic information replicated (cell reproduction)

Answer 12

For growth of an organism, cells must divide and replicate. Genetic info stored in DNA must be formed and passed onto daughter cells.

Question 13

What is cell replication generally carried out by?

Answer 13

Undifferentiated or stem cells

Question 14

What is mutation

Answer 14

Mistakes in the replications of DNA

Question 15

How can mutations be advantageous?

Answer 15

• Evolution of living organisms
• Basis of natural selection

Question 16

How can mutations be disadvantageous?

Answer 16

• Less effective function
• Death of the cell by carrying the mutant gene

Question 17

What are the 3 periods that occur during the division of any reproductively active cell?

Answer 17

• Interphase
• Mitosis
• Cytokinesis

Question 18

Describe the interphase period

Answer 18

• Longest phase & is the time between cell division
• The phase where major bodily functions are carried out
• Most cells are in the interphase state

Question 19

How many long chromatin threads does the interphase nucleus contain

Answer 19

46 (half from male and half female)

Question 20

What is mitosis?

Answer 20

The process of separating the 46 chromatin threads in each cell nucleus, to produce 2 identical sets of chromosomes in two separate nuclei.
- Provides the daughter cells with an identical set of DNA molecules

Question 21

What is Cytokinesis?

Answer 21

The process in which the cytoplasm of a single cell is divided to form two daughter cells

Question 22

What are the 4 types of cell tissues?

Answer 22

Epithelial, connective, muscular, nervous

Question 23

What is epithelial tissue for?

Answer 23

Protection, absorption, secretion, extretion

Question 24

What is connective tissue for?

Answer 24

support, packing material, defence

Question 25

What is muscular tissue for?

Answer 25

voluntary, involuntary, cardiac

Question 26

What is nervous tissue for?

Answer 26

Conductive, Support

Question 27

What is cell growth generally a result of?

Answer 27

1) Hyperplasia - increase number of cells
2) Hypertrophy - increase size of cell

Question 28

What does cancer result in?

Answer 28

Abnormal growth of cells. Arises when a cell doesn’t respond to the normal control mechanism and undergoes unlimited growth. Primary mechanism is hyperplasia and forms a tumour.

Question 29

Define metabolism

Answer 29

All the chemical reactions occurring in living matter.

Question 30

What law do all chemical reactions obey

Answer 30

Law of Conservation of energy

Question 31

Where does the energy come from to produce a chemical reaction?

Answer 31

Intrinsic heat (body heat)
Catabolism of carbohydrates, lipids etc.

Question 32

How does the Law of Conservation of Energy relate to chemical reactions in the body?

Answer 32

The difference in energy content between reactant and product molecules must equal the amount of energy added or released during the reaction
Release chemical energy appears mainly in the form of heat
Joules (calories)

Question 33

What is the function of ATP

Answer 33

transfer the energy released from the breakdown of carbohydrates etc. to the many different energy-requiring processes in the cell

Question 34

Describe ATP

Answer 34

Made up of 1 ADENOSINE molecule and 3 PHOSPHATE molecules. Held together by high energy phosphate bonds. The energy stored in the phosphate bonds is what is released to cause muscular contractions.

Question 35

What happens as a result of the catabolism of glucose to CO2 and H20

Answer 35

Energy is released
Achieved by Glycolysis and the Krebs cycle

Question 36

Where are the things that aren’t catabolised stored?

Answer 36

• Liver
• Muscle
• Synthesis of fat

Question 37

What is Glycolysis

Answer 37

Glycolysis is the breakdown of Carbohydrates (in the form of Glucose or Glycogen) into Pyruvic acid and two ATP molecules.

Question 38

Describe Carbohydrate catabolism

Answer 38

Food =carbohydrate & protein&raquo_space; carbohydrate&raquo_space;
- CATABOLISM&raquo_space; ATP + CO2 + H20
- ANABOLISM&raquo_space; glycogen/ fat

Question 39

Describe Fat catabolism

Answer 39

Food= fat & protein & carbohydrate&raquo_space; fat
fat&raquo_space; fatty acids & glycerol&raquo_space; acetyl coenzyme A&raquo_space; Krebs cycle (CO2) & coenzyme (2H)&raquo_space; Oxidative phosphorylation (O2 & H20)&raquo_space; ATP