Fuels

Question 1

What happens if there is a lack of oxygen (in terms of producing energy)

Answer 1

When there is a lack of oxygen, amino acids and fatty acids could be used and be implemented into this process to contribute to certain parts and ultimately contribute to cellular respiration

Question 2

Explain the process of oxidation of fatty acids and its contribution to energy production

Answer 2

They are long hydrocarbon chains. The fatty acid chains break into 2 carbon acetic acid molecules

Each acetic molecule combines with enzyme CoA to form acetyl CoA. The Acetyl CoA can be fed into the overall cellular respiration process and is used up in the Krebs cycle to produce NADH and ATP to be used in electron chain

Question 3

What is the structure of an amino acid

Answer 3

Has a nitrogenous portion and a carboxyl group (COOH)

Question 4

Explain the process of the oxidation of amino acids and its contribution to energy production

Answer 4

Amino acid degradation produces sugars that can be converted to glucose or utilised in Kreb’s cycle

The amino group (NH2) and extra H is used to remove it in the form of ammonia (NH3). The non nitrogenous portion (acid group) becomes a keto acid (ketone body)

These ketone bodies can be taken up from the blood and reconverted into acetyl CoA to be inserted into the Krebs Cycle

Question 5

What happens to amino acids in starvation conditions

Answer 5

They can be turned into pyruvate to be used (?)
not too sure about this one

Question 6

WHen O2 is available how can lactate contribute to energy production

Answer 6

Lactate can be converted into pyruvate to be used in further cell respiration

Question 7

What happens when oxygen is limiting (anaerobic conditions)

Answer 7

No krebs cycle, electron chain transport etc. because they require oxygen.

Instead, it relies on process of glycolysis of transfer from glucose to pyruvate which produces 2 ATP. However, this leads to a process of lactic acid fermentation

Question 8

What is lactic acid fermentation

Answer 8

This is when lactate production increases due to an increased demand for ATP which exceeds supply and oxygen is limiting

I.e. occurs during strenuous exercise, inadequate blood supply etc

Pyruvate is reduced to form lactate.

NADH is oxidised to NAD+

Ultimately 1 glucose molecule turns into 2 ATP, 2 x lactate

Question 9

Does our body exist in a dynamic catbolic-anabolic state

Answer 9

Yes. Some nutrients are used to build bits and pieces of you while others are broken down

Question 10

How long can nutrients absorbed from meals supply energy for

Answer 10

Around 4 hours

Nutrients stored as glycogen and fat to give energy until next meal

Question 11

What does our body do to get energy in fasting state

Answer 11

Rely on energy that has been stored (particularly glycogen)

Question 12

What are the preferred metabolic substrate(s) of the brain

Answer 12

Glucose (prioritise this)

(Ketone bodies under starvation)

Question 13

What are the preferred metabolic substrate(s) of the skeletal muscle

Answer 13

Fatty acids, glucose, ketone bodies

Question 14

What are the preferred metabolic substrate(s) of the heart muscle

Answer 14

Fatty acids, lactate, ketone bodies

Question 15

What are the preferred metabolic substrate(s) of the red blood cells

Answer 15

Glucose

A little bit of lactate

Question 16

What happens when the brain lacks glucose

Answer 16

Headache
Trembling
Sweatiness
Hunger
Blurry vision
Irritability
Ringing in ears
Feelings of anxiety
Increased heart rate
Weakness or tiredness

Question 17

How much atp does 1 gram of fatty acid produce

Answer 17

around 106 aatp

Question 18

How much atp is produced by glycolysis

Answer 18

2 ATP

Question 19

How much atp is produced by 1 gram of glucose (aerobic respiration)

Answer 19

~34 atp

Question 20

What are some uses of ATP

Answer 20

Energy source for >95% of cellular activity:

Contractility and motility (actin and myosin)

Ion pumps

Signalling

Biosynthesis

Heart uses around 0.135 micromols of ATP per second and around 6kg per day. Runs out of ATP within 10 seconds if ATP production is inhibited

Question 21

What happens to the brain, heart muscle and skeletal muscle in terms of preference for metabolic substrates during fasting state (4-30 hours)

Answer 21

Tissues other than brain reduce glucose usage (because prioritising glucose to go brain)

Brain uses glucose produced from glcogen and amino acids in liver

Question 22

What happens to the brain, heart muscle and skeletal muscle in terms of preference for metabolic substrates during starving state (after 30 hours)

Answer 22

Brain starts using ketone bodies rather than glucose

Other tissues stop using glucose

Liver makes ketone bodies from fatty acids

Liver and kidney make glucose from amino acids –> loss of muscle mass

Question 23

What is keto acidosis

Answer 23

High serum and urine concentration of ketone bodies

Question 24

What is diabetic ketoacidosis

Answer 24

Life threatening complication of diabetes.

It occurs when the body starts breaking down fat at a rate that is much too fast. The liver processes the fat into a fuel called ketones, which causes the blood to become acidic.

Question 25

What is starvation ketoacidosis

Answer 25

Occurs when body is deprived of glucose and relies on fatty acids

Question 26

What is our breath smelling like acetone a sign of

Answer 26

Ketosis is a metabolic state that occurs when your body burns fat for energy instead of glucose.