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ESA1 Callum's cards > Metabolism S1 - Nutrition, Diet, Homeostasis and Energy reactions in cells > Flashcards

Metabolism S1 - Nutrition, Diet, Homeostasis and Energy reactions in cells Flashcards

1
Q

What are the features of catabolic pathways in metabolism?

A

Break down of molecules (large to small)

Releases energy (some conserved as ATP)

Produces reducing power (release of H+)

Produces intermediary metabolites

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2
Q

What are the features of anabolic pathways in metabolism?

A

Builds smaller molecules into larger ones

Reductive (uses H+ ions)

Uses intermediary metabolites and energy as ATP to synthesise new cell components

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3
Q

What is the daily energy expenditure of a 70kg male?

A

12,000kJ

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4
Q

What is the daily energy expenditure of a 58kg woman?

A

9,500kJ

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5
Q

Daily energy expenditure is comprised of what 3 basic components?

A

Energy to support base metabolism (basal metabolic rate)

Energy for voluntary physical exercise

Energy to process food we eat (diet induced thermogenesis)

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6
Q

List the essential components of the diet

A

Fats

Carbohydrates

Proteins

Water

Fibre

Minerals and vitamins

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7
Q

Why are fats essential to diet?

A

Necessary to absorb fat soluble vitamins (ADEK)

Contain essential fatty acids (eg linoleic and linolenic acids)

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8
Q

What is the energy yield of fats compared to carbohydrates?

A

2.2 times greater

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9
Q

What are the fatty acids linolenic acid and linoleic acid used for?

A

Structural components of cell membrane

Precursors of important regulatory molecules (eicosanoids)

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10
Q

Why are proteins essential components of the diet?

A

Amino acids used in synthesis of N containing compounds (eg. Creatine, nucleotides, haem)

Maintain nitrogen balance

Contain essential amino acids that can’t be synthesised by the body.

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11
Q

What is the nitrogen balance?

A

Intake of N2 = N2 loss daily

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12
Q

How much protein is degraded and excreted per day and hence what is the daily protein requirement in the diet?

A

Average 35g degrades

35g intake required to maintain nitrogen balance

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13
Q

Why are carbohydrates and essential dietary requirement?

A

Main source of energy in diet

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14
Q

What is the energy content of carbohydrates per gram?

A

17kJ/g

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15
Q

Are fats necessary for energy production?

A

Nope

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16
Q

Why is water an essential dietary component?

A

Water lost by the body each day, must be replaced by drinking

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17
Q

What proportion of the body weight is water?

A

50-60% adult

70% child

~50% elderly/obese

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18
Q

How much water is lost to the body a day and how is it lost?

A
  1. 5L lost total
  2. 5L urine
  3. 4L expired air
  4. 5L skin/sweat
  5. 1L Faeces
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19
Q

How is water gained by the body?

A

Drinking

Cellular metabolism (0.35L)

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20
Q

Why is fibre necessary in the diet?

A

Normal bowel function

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21
Q

Why are minerals and vitamins necessary in the diet?

A

Deficiency/absence/excess of these associated with disease.

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22
Q

In adults what can starvation lead to?

A

Muscle and subcutaneous fat wasting as fat and protein reserves used for energy.

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23
Q

What are the common complaints of starvation?

A

Cold, muscle weakness, GI tract and lung infections common

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24
Q

What is marasmus?

A

Protein-energy deficiency most commonly seen in children under 5

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25
Q

What are symptoms of marasmus?

A

Emaciated appearance (muscle and fat wasting)

Hair is thin/dry

Diarrhoea/anemia commonly present

NO oedema

26
Q

What is kwashiorkor?

A

Form of malnutrition typically found in young children that stop breast feeding to early and are fed a low protein diet with some carbohydrate.

27
Q

What are the common complaints in a child with kwashiorkor?

A

Apathy

Lethargy

Anorexia

Distended abdomen

Generalised oedema

Anaemia common

28
Q

Why is the abdomen distended and generalised oedema seen in children with kwashiorkor?

A

Distended abdomen due to hepatomegaly (enlarged liver) and/or ascites (fluid in peritoneal cavity)

Generalised oedema due to low serum albumin (low blood osmotic pressure)

29
Q

How is BMI calculated?

A

Weight (kg) / (height (m) squared)

30
Q

How is BMI interpreted?

A

Underweight = <18.5

Desirable range = 18.5 - 24.9

Overweight = 25 - 29.9

Obese = 30 - 34.9

Severely obese = >35

31
Q

Define obesity

A

Excess body fat accumulation that may have adverse effect on health leading to reduced life expectancy and/or increased health problems

32
Q

What leads to changes in body weight?

A

Differences between input of substances and output of substances and energy will lead to increase or decrease in body weight

33
Q

Define homeostasis then explain its importance and what it controls.

A

The maintenance of a stable internal environment.

A dynamic equilibrium that acts to counteract changes in the internal environment

Occurs at all levels from cellular to organ/system to whole body

Controls supply of nutrients, oxygen, blood flow, temperature, removal of waste and pH

Failure of homeostasis leads to disease

34
Q

What are the 2 major communication pathways of the body?

A

Nervous and endocrine

35
Q

What is paracrine control?

A

Local release of hormones (via ducts/exocrine)

36
Q

What is autocrine control?

A

Release of agent which affects the releasing cell.

37
Q

What two categories can the peripheral nervous system be sorted into?

A

Efferent - motor output

Afferent - sensory input

38
Q

What are the major features of the bodies control system?

A

Communication

Control centre

Receptor

Effector

39
Q

What are the functions of the control centre of the body’s control system

A

Establishes reference set points

Analyses afferent input and determines response

40
Q

Where is the hypothalamus and what does it control?

A

Found in the diencephalon

Involved in control of the endocrine system

41
Q

Where is the medulla oblongata and what functions is it involved in?

A

Found in brainstem

Involved in control of ventilation and cardiovascular system.

42
Q

What are receptors in the PNS of the body involved in?

A

Detect stimuli with specialised nerve endings and communicate this to the CNS via afferent nerves

43
Q

What is the function of effectors?

A

Cause change when prompted by efferent nerve stimulation

44
Q

Are set points of control by the CNS fixed?

Give an example of set point control

A

No, they can vary over time

Eg. Cortisol peaks around 7am and troughs around 7pm this is known a circadian rhythm.

45
Q

The menstrual cycle is a good example of what?

A

A biological rhythm, a woman’s core body temperature varies throughout the cycle. (Sharp increase indicates ovulation).

46
Q

Define cell metabolism

A

Highly integrated network do chemical reactions comprised of a series of metabolic pathways (some specific to specialised cells, some general).

47
Q

What are the functions of cell metabolism?

A

Metabolise nutrients to produce a variety of products.

48
Q

What is produced by cell metabolism and what are the products used for?

A

Energy for cell function - produces ATP

Building block molecules - used in the synthesis of cell components needed for growth, repair and division of the cell

Organic precursor molecules - used to interconvert building block molecules (eg. AcetylCoA)

Biosynthetic reducing power - used in the synthesis of cell components (eg NADPH)

49
Q

Where do cell nutrients in the blood come from?

A

Diet

Synthesis in other tissues

Release from storage in other tissues

50
Q

What are cell nutrients used for?

A

Degradation for energy release

Synthesis of cell components

Storage - (only in liver, adipose tissue, skeletal muscle)

51
Q

Why do cells need a continuous supply of energy?

A

To maintain function

52
Q

Explain the concept of energy coupling and how it’s performed.

A

Transferring energy released in exergonic reactions to endergonic reactions. This is performed by intermediary molecules of the ADP/ATP cycle.

53
Q

Name three high energy phosphorylated compounds and give the energy released by their hydrolysis

A

Phosphoenolpyruvate = -62kJ.mol-1

Creatine phosphate = -43kJ.mol-1

ATP = -31kJ.mol-1

54
Q

What is the equation for hydrolysis of ATP or ADP ans how much energy is released?

A

ATP + H2O <–> ADP + Pi

ADP + H2O –> AMP + Pi

Releases -31kJ.mol-1

55
Q

What is Creatine phosphate used for?

A

To provide a store of high energy molecules that can be used immediately for metabolism in high activity tissues eg. muscle

56
Q

What is the reaction for the phosphorylation of Creatine, what enzyme is involved and how is it controlled?

A

Creatine + ATP <–> Creatine phosphate + ADP

When ATP is high forward reaction favoured

Catalysed by Creatine kinase

57
Q

How is ATP involved in regulation of metabolism?

A

High ATP concentration leads to activation of anabolic pathways

Low ATP concentration leads to activation of catabolic pathways

58
Q

What signals a cell has adequate energy?

A

High levels of ATP as well as reducing agents such as FADH/NADHH/NADPH are high energy signals

59
Q

What signals a cell has low energy?

A

High levels of ADP and NAD+/FAD/NADPH+

60
Q

Carrier molecules such as NAD+ are derived from what type of molecule?

A

B vitamins

61
Q

What can be said about the total amount of H+ carrier molecules in the body?

A

Total amount is constant

ESA1 Callum's cards (34 decks)

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