Bioengenetics

Question 1

What is photosynthesis?

Answer 1

• Chemical endothermic reaction converting light energy
• To chemical energy in the form of glucose
• Providing the organism with energy

Question 2

Word and Symbol equation for photosynthesis

Answer 2

Carbon Dioxide + Water –> Glucose + Oxygen

6CO2 + 6H2O –> C6H12O6 + 6O2

Question 3

How does temperature affect the rate of Photosynthesis?

Answer 3

• Increasing temp catalyses rate of reaction, so it increases
• Optimal temperature is perfect
• If temperature exceeds optimal the enzyme becomes denatured
• So rate of reaction decreases

Question 4

How does Light Intensity affect the rate of photosynthesis?

Answer 4

• AS light intensity increases

- Rate of photosynthesis increases too

Question 5

How does CO2 affect the rate of Photosynthesis?

Answer 5

• As CO2 increases

- Rate of photosynthesis increases

Question 6

What is a LIMITING FACTOR?

Answer 6

Something present in the environment in such short supply that it restricts other living processes from occurring

Question 7

What are some examples of limiting factors for photosynthesis?

Answer 7

LIGHT, TEMPERATURE, CO2

Question 8

What is the Inverse Square Law?

Answer 8

• If you double the distance from the light source to the plant
• The number of bubbles per minute falls by a factor of 4

Light intensity = 1 / d^2

Question 9

How can the glucose from photosynthesis be used?

Answer 9

• Respiration
• Converted into insoluble starch
• Producing fat or oil storage
• Produce cellulose
• Producing amino acids

Question 10

What mineral from the soil does a plant use to make amino acids?

Answer 10

Nitrate ions

Question 11

What does respiration allow the plants to do?

Answer 11

To convert the rest of the glucose into useful substances for growth

Question 12

Investigate how certain environmental factors change the rate of photosynthesis?

Answer 12

One adds PONDWEED to a SODIUM HYDROGEN CARBONATE solution in a boiling tube, (SHC releases CO2, which is necessary for photosynthesis)

Leave this for 5 mins in order to ACCLIMATISE to the conditions of the boiling tube

Gas will be produced in bubbles, (Product of photosynthesis is OXYGEN)

Count the number of bubbles per minute (find the mean) and reconduct the experiment at different distances from light source.

Record results and plot a graph.

Question 13

Word equation for Respiration?

Answer 13

Glucose + Oxygen –> Carbon Dioxide + Water + Energy

Question 14

What is cellular respiration?

Answer 14

An exothermic reaction which is continuously occurring in living cells, releasing energy

Question 15

Why do organisms need energy?

Answer 15

• Chemical reactions, to build larger molecules
• Movement
• Keeping warm

Question 16

What is anaerobic respiration?

Answer 16

The incomplete breakdown of glucose into LACTIC ACID

Glucose –> Lactic Acid

Gives far less energy than aerobic respiration

Question 17

What is anaerobic respiration in yeast?

Answer 17

Fermentation

Glucose –> Ethanol + Carbon Dioxide

Question 18

Why is fermentation important?

Answer 18

Has economic importance in the manufacture of bread and alcoholic drinks

Question 19

How can the human body react to increased demand of oxygen?

Answer 19

• Heart rate quickens
• Breathing rate quickens
• Breath volume increases

Question 20

What occurs in the body during vigorous exercises when insufficient oxygen is supplied to the body?

Answer 20

Anaerobic Respiration takes place

Question 21

What happens when there is an incomplete combustion of glucose in the muscles?

Answer 21

• Build up of lactic acid occurs
• Causing muscles to not be able to contract efficiently due to fatigue
• Oxygen debt builds up

Question 22

How does our body deal with oxygen debt?

Answer 22

• It can be oxidised to form CO2 and H2O

- Or blood flowing through the muscles can transport the lactic acid to the liver where it is converted back to glucose

Question 23

What is metabolism?

Answer 23

The sum of all the reactions in a cell or the body

Question 24

How can energy transferred by respiration in cells be used by the organism metabolically?

Answer 24

Used for continual enzyme controlled processes of metabolism that synthesize new molecules

Question 25

What does metabolism include

Answer 25

• Conversion of glucose to STARCH, GLYCOGEN and CELLULOSE
• Formation of lipid molecules from glycerol and 3 molecules of fatty acids
• Use of glucose and nitrate ions to form amino acids (to synthesise proteins)
• Respiration
• Breakdown of excess proteins to form urea for excretion

Question 26

What is a substrate?

Answer 26

• Temporarily binds to the active site of an enzyme

- Leads to a chemical reaction

Question 27

How does the relationship with enzymes and substrates work?

Answer 27

• Both randomly move around in solution
• Enzyme and its complementary substrate collide randomly
• Enzyme-substrate complex forms, reaction occurs
• A product (or products) forms from the substrate which are released from the active site

Question 28

How does temperature affect enzymes?

Answer 28

• Too low and the enzymes will not be effective and work too slow (less kinetic energy so lower rate of reaction)
• Optimum, and the enzymes will work at a good rate (collision theory)
• Too high, and enzymes will become DENATURED where the active site loses shape so substrates cannot lock on

Question 29

What are the 3 main digestive enzymes?

Answer 29

Carbohydrases, proteases and lipases

Question 30

What are proteases?

Answer 30

• Enzymes which break down carbohydrates into SIMPLE SUGARS

Such as amylase breaking down STARCH into MALTOSE, which is then broken down to glucose by MALTASE

Question 31

What are proteases?

Answer 31

• Enzymes which break down proteins into AMINO ACIDS

Question 32

What are lipases?

Answer 32

Enzymes which break down LIPIDS (fats) into GLYCEROL (and fatty acids)