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IB Biology Option D: Human Physiology > D1 > Flashcards

D1 Flashcards

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1
Q

What does the diet consist of ?

A 
Carbs
Lipids
Proteins
Dietary Minerals 
Vitamins and Trace Elements 
Water 
Fibre 
mnemonic: Van Dijk likes playing Football wearing crocs.
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2
Q

From what can Glycerol be synthesised?

A

Glucose

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3
Q

What is an example of an essential fatty acid ?

A

Linoleic Acid (e.g. sunflower seeds)

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4
Q

How many of the 20 amino acids are essential ?

A

9 e.g. leucine

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5
Q

For which people is Arginine essential ?

A

Infants and Children; adults can synthesise it

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6
Q

What makes Tyrosine conditionally essential?

A

It can be synthesised, but only if Phenylalanine is present

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7
Q

Dietary Minerals are essential, what are some examples of their use ?

A

Calcium - Bones and Teeth

Phosphorous - Bones, Teeth, Nucleic Acids, and ATP.

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8
Q

What are Vitamins?

A

Chemically diverse carbon compounds

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9
Q

Which vitamins are non-essential?

A

K & H; they can be synthesised by bacteria in the large intestine.

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10
Q

What are some essential vitamins ?

A

A, B, and C

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11
Q

Is vitamin D essential ?

A

Vitamin D is conditionally essential.

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12
Q

Outline the solubility of vitamins

A

Vitamins are either Water or Fat soluble.
Water soluble vitamins (e.g. B&C) are excreted if not required by the body.
Fat soluble vitamins (e.g. A&D) can be stored.

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13
Q

What are examples of Trace elements ?

A

Trace elements are essential:
Iron for haemoglobin and myoglobin
Cobalt for red blood cell development
fluorine for tooth enamel

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14
Q

What is Vitamin C

A

Abscorbic Acid; it can be synthesised by some mammals, but not by humans.

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15
Q

What is the importance of fibre ?

A

Cellulose cannot be digested but is important for maintaining the strength of the gut muscles for peristalsis.

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16
Q

What is Vitamin C used for ?

A

Vitamin C is required by the body to synthesise collagen fibres. These are used in skin,tendons,ligaments, and the walls of blood vessels.

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17
Q

What does a lack of vitamin C cause? What are some good sources of vitamin C ?

A

Scurvy; citrus fruits are rich in vitamin c but cooking destroys it.

18
Q

How is appetite controlled?

A

Hormones from the:
Pancreas; lowers blood sugar levels

Small Intestine; where end products of digestion absorbed

Adipose Tissue; where fat is stored

The hormones from these regions stimulate the appetite control centre. When sufficiently stimulated the appetite control centre sends another signal of the brain to create the feeling of ‘being full’.

19
Q

When do the Small Intestine and Pancreas release appetite controlling hormones?

A

When food enters the small intestine

20
Q

When does adipose tissue release appetite controlling hormones?

A

In response to the uptake of fat into the cells

21
Q

Where is the Appetite Control Centre?

A

Hypothalamus

22
Q

What causes people to be overweight?

A

Having a diet with excess amounts of fatty and sugary food and drink.
Insufficient exercise

23
Q

What are the consequences of being overweight?

A

Type II Diabetes

Hypertension

24
Q

What is Hypertension?

A

Raised Blood Pressure, normal is 100-140/60-90

Thus, pressure over 140/90mm Hg is hypertension

25
Q

Outline the correlation between being overweight and hypertension

A

Greater tissue mass means enlarged capillary network with a higher resistance to blood flow.
Heart Output has to increase
Arteries become narrowed and lose elasticity

26
Q

How does high levels of salt raise blood pressure?

A

Blood concentration rises so the kidneys retain water through osmoregulation.
A greater blood volume raises pressure.

27
Q

Define Starvation

A

Severe nutritional deficiency.

28
Q

What are the symptoms of starvation?

A
  • Body mass decreases due to loss of fat and skeletal muscle
  • Hair thins
  • Skin becomes dry and bruises easily
  • Heart rate slows -> low blood pressure and poor circulation.
  • In females, menstruation and ovulation cease.
29
Q

What is the result of starvation?

A

Insufficient amino acids, vitamins and minerals in the diet cause the breakdown of muscle fibres. These are primarily skeletal, but eventually cardiac muscle is affected.

30
Q

What is Anorexia

A
  • Anorexia means reduced appetite and research indicates it has a genetic basis.
  • Anorexia Nervosa is a psychiatric condition which can result in severe weight loss and even death.
31
Q

Outline causes of Phenylketonuria (PKU)

A
  • Phenylalanine is normally converted into Tyrosine by phenylalanine Hydroxylase.
  • In PKU, a recessive mutation of the gene for this enzyme means Phenylalanine accumulates in the blood.
32
Q

What are the Consequences of PKU

A
  • While a fetus, the excess Phenylalanine diffuses across the placenta and is rremoved by the mother.
  • After birth, accumulation of Phenylalanine in the baby’s blood leads to severe mental retardation, hyperactivity, and seizures as they grow.
33
Q

How is PKU diagnosed and treated ?

A
  • Diagnosed by a simple blood test 24 hours after birth.
  • Treated by consuming very low amounts of Phenylalanine; Breast milk is low in phenylalanine and can be supplemented with low phenylalanine formula milk.
  • After weaning, the diet must avoid proteins high in Phenylalamnine such as meat,eggs,beans, and nuts.
  • It may also be necessary to add supplementary Tyrosine.
34
Q

What is Vitamin D required for?

A

Absorption of Calcium ions in the gut; thus the symptoms of calcium deficiency are similar to those of vitamin d deficiency.

35
Q

What can a lack of calcium or vitamin D result in?

A

Weak Bones - Osteomalacea or Rickets

36
Q

How is vitamin D made?

A

when the skin is exposed to sunlight.

37
Q

Can vitamin D be stored ?

A

Yes, it is fat soluble. This is important for storing reserves during winter in high latitudes, as sunlight is limited.

38
Q

What is Cholesterol?

A
  • A steroid that is an important component of cell membranes.
  • All the cholesterol required by the body is synthesised by the Liver, dietary cholesterol has little impact on blood cholesterol.
39
Q

Outline the bad effects of consuming too much saturated fats

A
  • Saturated fat increases the level of LDL (more cholesterol than HDL) in the blood.
  • High levels of LDLs in the blood can lead to Atherosclerosis and Coronary heart Disease.
40
Q

How is the energy content of food determined?

A

Calorimetry

  • Takes 0.0042kJ of energy to raise 1g of water by 1c.
  • Dry food sample is weighed, then completely burned in a highly insulated container surrounded by water.
  • Water temperature rise is measured.
  • Energy Content (Q) is given by: Q = mass of water x rise in temperature of water x 0.0042
41
Q

What is the formula for determining the energy content of food

A

Energy Content (Q) is given by: Q = mass of water x rise in temperature of water x 0.0042

42
Q

What are the approximate energy contents of 1 g of the major food groups ?

A

Carbs: 17kJ^-1
Lipids: 38kJ^-1
Proteins: 17kJ^-1

IB Biology Option D: Human Physiology (2 decks)

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