Energy Reactions In Cells

Question 1

What are the 3 components of the daily expenditure?

Answer 1

BMR (basal metabolic rate)
Voluntary physical activity
Diet induced thermogenesis

Question 2

What is the BMR?

Answer 2

It is the energy used to maintain life (ie when you’re resting)

Question 3

Factors that affect the BMR

Answer 3

Body size
Gender (lower for women)
Environmental temperature
Endocrine status

Question 4

Major tissues contributing to BMR

Answer 4

Skeletal muscle
CNS
Liver
Heart

Question 5

What is diet induced thermogenesis?

Answer 5

It is the energy required to process the food = about 10% of the foods content

Question 6

Essential components of the diet

Answer 6

Fats (about 30% of RDA) 37kj/g
Proteins (about 15%) 17kj/g
Carbs (about 55%) 17kj/g
Water 
Fibre 
Minerals and vitamins

Question 7

Why are fats essential?

Answer 7

• Necessary for absorption of vitamins ADEK
• Essential fatty acids (linoleic and linolenic) are structural components of cell membranes and important precursors of important regulatory molecules

Question 8

Why is fibre essential?

Answer 8

Necessary for normal bowel function

Question 9

Signs of starvation in adults

Answer 9

• loss of weight due to subcutaneous fat+muscle wasting
• complain of cold and weakness
• infections if GI tract and lungs are common

Question 10

Describe marasmus

Answer 10

• inadequate protein and calorie intake
• mainly seen in children under 5
• no oedema
• looks emaciated with signs of muscle wasting and loss of body fat leading to a thin bony appearance
• hair is dry and thin
• common diarrhoea
• may have anaemia

Question 11

Describe kwashiorkor

Answer 11

• adequate calories with Inadequate protein
• child is apathetic, lethargic and anorexic
• oedema
• abdomen distended due to hepatomegaly or/and ascites
• serum albumin low + anaemia common

Question 12

Define homeostasis

Answer 12

Control of internal environment with set limits and is a dynamic equilibrium not a fixed steady state

Question 13

Difference between catabolism and anabolism

Answer 13

ANABOLISM = building large molecules, reductive (uses H+), uses intermediate metabolites and induced by high energy signals

CATABOLISM= breaking down large molecules, oxidative, releases large amounts of free energy, produces intermediate metabolites and uses low energy signals

Question 14

Carrier molecules :

Answer 14

Oxidised = NAD+                   NADP+                   FAD
Reduced= NADH &H+           NADPH&H+           FAD2H

Question 15

High energy signals

Answer 15

ATP
NADH
NADPH
FAD2H

Question 16

Creatine phosphate reaction

Answer 16

Creatine +ATP Creatine phosphate + ADP

*catalysed by Creatine kinase

Question 17

What happens to Creatine phosphate when [ATP] is high ?

Answer 17

Lots more Creatine phosphate is made

Question 18

What is creatinine ?

Answer 18

• It is produced when Creatine and Creatine phosphate both undergo non-enzymatic chemical changes producing creatinine.
• Creatinine has no bodily function and is excreted in the urine.
• Rate of production if creatinine is proportional to the conc of Creatine in muscle and related to skeletal muscle mass.
• Measurements if [creatinine] in the blood and urine can be a useful indicator of kidney function.

Question 19

Obesity can lead to ……….

Answer 19

Hypertension, heart disease, type2 diabetes, certain cancers, gall bladder disease and osteoarthritis