Metabolism

Question 1

Anabolism

Answer 1

• Metabolic reactions that build up and require energy (=endothermic reactions)
• E.g., linking glucose units to form glycogen or linking amino acid units to build proteins
• Construct things and consume energy

Question 2

catabolism

Answer 2

• Metabolic reactions that break down and release energy (=exothermic reactions)
• E.g., breakdown of fat tissue or glycogen for energy supply
• Break down bigger molecules and release energy

Question 3

cellular respiration

Answer 3

• Energy is derived from the breakdown of nutrients to carbon dioxide and water
• 3 main sources of energy: carbohydrates, fat, and protein
• Main substance oxidized within the body is glucose (a sugar)

Question 4

water

Answer 4

about 70% of the animal’s body weight is made up of water

Question 5

carbohydrates

Answer 5

• monosaccharides, disaccharides, polysaccharides
• glycogen (after digestion a part of glycose is unused and will be stored as glycogen (polysaccharide storage) in liver and muscle
• cellulose

Question 6

monosaccharides

Answer 6

one-sugar molecules, absorbable units (glucose, fructose)

Question 7

disaccharides

Answer 7

two-sugar molecules, hydrolyzed into monosaccharides with enzymes (maltose, lactose)

Question 8

polysaccharides

Answer 8

many-sugar molecules, chains of interconnected monosaccharide molecules (starch, cellulose)

Question 9

vitamins

Answer 9

organic nutrients required in metabolic reactions, such as helping enzymes

Question 10

energy and ATP

Answer 10

• Energy is not a substance, needs a carrier
• In the body: ATP – adenosine triphosphate
• Pathway depends on the presence of oxygen (aerobic vs. anaerobic energy production)

Question 11

what are the sources ATP can be produced from (3)

Answer 11

• Glycogen stores in the muscle
• Glycose from the blood
• Fatty acids from the blood

Question 12

ATP
what does it consist of

Answer 12

• Consists of adenosine, ribose, and three phosphate groups
• Energy is contained in the bonds of the phosphate groups, release of 1 P leaves ADP (adenosine diphosphate) and a single phosphate (used for making more ATP)

Question 13

what are the four stages of cellular respiration

Answer 13

glycolysis, formation of acetyl CoA, citric acid cycle, electron transport and chemiosmosis

Question 14

glycolysis (in cytosol)

Answer 14

• Series of reactions in which glucose is degraded to pyruvate
• Net profit of 2 ATPs
• Hydrogens atoms are transferred to carriers
• Can proceed anaerobically
• Starting materials:
• Glucose, ATP, NAD+, ADP, P
• End products:
• Pyruvate, ATP, NADH

Question 15

Special proteins: Enzymes
How do they work and what do they do?

Answer 15

• control and speed up specific chemical reactions in the body
• are reusable
• can work intracellular or extracellular

Question 16

Lipids -> Triglycerides

Answer 16

• combination of glycerol with 3 fatty acid molecules attached
• during digestion, 2 FA molecules split off, leaving a monogylceride
• end products: monoglycerides and free acids
• Triglycerides can be stored in adipose tissue

Question 17

Proteins
Where do they play a role? (6)

Answer 17

• defense
• storage
• transport
• cellular communication
• movement
• structural support

Question 18

Cellulose

Answer 18

• major component in plant material
• cannot be hydrolyzed with enzymes by the animal
• can be broken down by symbiotic microorganisms living in the digestive tract -> fermentation -> end products: VFA (used as energy source

Question 19

Lipids

Answer 19

• highly concentrated source of energy
• made of carbon, hydrogen, and oxygen

Question 20

Proteins
What are they composed of?

Answer 20

• various linear sequences of 20 different amino acids

Question 21

What influences the activity of enzymes?

Answer 21

• temperature: they are inactivated or damaged by heat
• pH: most prefer neutral pH