Cells Undergo Chemical Reactions [3]

Question 1

What is metabolism

Answer 1

All chemical reactions that take place in a cell to keep it alive

Question 2

Compare catabolism and anabolism and provide an example for each

Answer 2

Catabolism - molecules are broken down and release energy e.g. digestion

Anabolism - small molecules build up to form larger ones, consume energy e.g. protein synthesis

Question 3

Define nutrients and its six groups

Answer 3

Substances used for growth, repair or maintenance

Water, carbohydrates, lipids, proteins, minerals, vitamins

Question 4

What are organic compounds and examples

Answer 4

Molecules with a carbon chain

Carbohydrates, lipids, proteins, nucleic acids

Question 5

Are carbohydrates organic or inorganic, and what elements make up carbs

Answer 5

Organic (contain carbon, hydrogen, oxygen)

Question 6

What are the three levels of carbohydrates

Answer 6

Polysaccharides, disaccharides, monosaccharides

Question 7

What are carbohydrates

Answer 7

Main source of energy for cells, simple sugars that are used in cellular respiration to release energy

Question 8

What are monosaccharides and name 3 examples

Answer 8

“Simple sugars”, they are single-unit sugars.

Glucose, fructose, galactose

Question 9

What are disaccharides and name 3 examples

Answer 9

Two simple sugars joined together

Sucrose, maltose, lactose

Question 10

What are polysaccharides and name 3 examples

Answer 10

Chains of simple sugars joined together

Glycogen, cellulose, starch

Question 11

What do complex carbohydrates do

Answer 11

Break down to simple sugars, which are broken down during cellular respiration for energy

Question 12

What are lipids and their purpose

Answer 12

Fats made of glycerol and fatty acid chains (both including carbon, oxygen and hydrogen)

They are broken down so glycerol can enter glycolysis pathway and produce energy

Question 13

What are proteins?
(composition, purpose)

Answer 13

100 or more layered amino acids, each protein is unique based on its amino acid structure

Contain carbon, hydrogen, oxygen and nitrogen

Used for tissue growth/repair, enzyme production

Question 14

What is the composition of amino acids, and what do they do besides forming proteins?

How many amino acids are there?

Answer 14

Molecule that contains an amino group, and a carboxylic acid group

20 different amino acids

2 acids react to form a peptide bond and water molecule

Question 15

Difference between polypeptides and dipeptides

Answer 15

Dipeptide - 2 amino acids joined

Polypeptide - >10 acids

Question 16

What are nucleic acids
(chemical composition, structure, examples)

Answer 16

Large molecules with carbon, hydrogen, oxygen, phosphorous

Made up of nucleotides (nitrogen base, sugar, phosphate)

DNA and RNA

Question 17

What are inorganic compounds and examples

Answer 17

Compounds not based on a carbon chain

Water, vitamins, minerals

Question 18

Why is water important in metabolism

Answer 18

Dissolves other substances

Chemical reactions occur in water

Question 19

What are minerals and its role in metabolism

Answer 19

Inorganic elements required by the body for development and function

Act as cofactors for enzymes, may be part of substances involved in metabolism (e.g. ATP)

Question 20

What is are vitamins and their role in metabolism

Answer 20

Inorganic compounds acting as coenzymes for chemical reactions

Question 21

What are enzymes?

Answer 21

PROTEINS that speed up chemical reactions (organic catalysts) by lowering activation energy

Allow body reactions to proceed at a sufficient rate

Work on substrates

Question 22

Describe the lock and key model

(4 STEPS)

Answer 22

1) Enzyme joins with its complementary substrates

2) Form an enzyme-substrate complex

3) Complex breaks apart into one enzyme and 2 products

4) Enzyme shape remains the same and can be reused

Question 23

What are the 6 factors of enzyme activity?

Answer 23

Enzyme & substrate concentration

Removal of products - easier contact

Temperature

pH scale - each enzyme has its own optimal level

Cofactors & coenzymes - changes shape of active site

Enzyme inhibitors

Question 24

What is the optimal temp for enzyme activity and why?

Answer 24

30 - 40 °C, as a higher temp means deformed proteins and a lower temp means too slow

Question 25

What is cellular respiration?

Answer 25

A metabolic process where organic molecules are broken down to provide energy for the cell

Question 26

What are the organic molecules used in cellular respiration, and how are they formed?

Answer 26

Glucose - breakdown of complex sugars Amino acids - breakdown of proteins Fatty acids and glycerol - breakdown of lipids

Question 27

Describe the structure of an ATP molecule and how it is formed

Answer 27

Adenosine ( 2 adenine and 1 sugar ribose ), and triphosphate ( 3 phosphate groups with high energy bonds ) Formed when a phosphate group is added to ADP

Question 28

What is ATP and its purpose?

Answer 28

A molecule that transfers energy to where it is needed. Releases energy when the bonds between phosphate groups are broken

Question 29

What is the chemical equation for cellular respiration, and what does it actually mean?

Answer 29

C⁶H¹²O⁶ + 6O² —> 6CO² + 6H²O + energy Is actually >20 steps, each catalysed by enzymes and releasing compounds and energy.

Question 30

Describe glycolysis

Answer 30

Glycolysis (spitting glucose) occurs in cytosol. 1 glucose molecule breaks down into 2 pyruvate (pyruvic acid) and 2 ATP molecules. No oxygen needed

Question 31

Where does anaerobic respiration occur?

Answer 31

Cytosol

Question 32

When does anaerobic respiration occur, and why?

Answer 32

No oxygen present, so it forms ATP by converting pyruvate into lactic acid. No water is produced.

Question 33

What happens to lactic acid after anaerobic respiration

Answer 33

Converted back to glucose for aerobic respiration when oxygen is available

Question 34

What happens during aerobic respiration? What is required for it to happen? Where does it take place?

Answer 34

Glucose completely breaks down into CO², H²O and ATP. Oxygen is required Mitochondria

Question 35

How much ATP can one cycle of aerobic respiration can be produced

Answer 35

Up to 38

Question 36

Name the steps in aerobic respiration (4 steps total) Don't describe

Answer 36

1) Glycolysis 2) Conversion of pyruvate into CoA 3) Krebs / Citric Acid Cycle 4) Electron Transport System

Question 37

Summarise the products at each phase of aerobic respiration (glycolysis, CoA conversion, Krebs cycle, electron transport system)

Answer 37

Glycolysis - 2 pyruvate, 2 ATP CoA conversion - 2 acetyl Coa Krebs cycle - 2 ATP and 2 CO² Electron transport system - up to 34 ATP, water 34+2+2 = 38 ATP

Question 38

What happens during pyruvate conversion

Answer 38

Pyruvate converted into acetyl coenzyme A (acetyl CoA) by removing CO2 and joining the remaining carbon atoms

Question 39

What happens during Krebs cycle

Answer 39

Carbon atoms in acetyl CoA are released in CO2. For every acetyl CoA entering this cycle, 1 ATP is produced

Question 40

What happens during electron transport system

Answer 40

Only phase that uses oxygen - electrons are passed between molecules, making oxygen molecules from water. Forms 26-34 ATP

Question 41

Describe the types of energy produced in respiration and its uses

Answer 41

Chemical energy from glucose turns into: 60% heat energy (used for homeostasis) 40% chemical energy in ATP (used for many bodily functions, e.g. cell growth, movement, division, transport, nerve impulse transmission, etc)

Question 42

Co-factors

Answer 42

Change shape of enzyme to bond with substrate Vitamins

Question 43

Enzyme inhibitors

Answer 43

Slow/stop reactions to produce specific amounts of product