nutrition diet and body weight

Question 1

define metabolism

Answer 1

the chemical processes that occur within a living organism in order to maintain life

Question 2

functions of metabolism

Answer 2

oxidative pathways : convert food to energy
fuel storage and mobilisation pathways:allow fuel to be mobilised when we are not eating or need increased energy.
biosynthetic pathways: produce basic building blocks for cells
detoxification pathways: remove toxins

Question 3

define energy

Answer 3

capacity to do work

Question 4

Why do living cells require energy

Answer 4

biosynthetic work- synthesis of cellular components
transport work across cell membranes- maintenance of ion gradients, uptake of nutrients
mechanical work- muscle contraction
electrical work-nervous conduction
osmotic work- kidney

Question 5

define exergonic and endergonic

Answer 5

exergonic- energy released is greater than energy input

endergonic- energy input is greater than energy released

Question 6

describe the ATP-ADP cycle

Answer 6

ADP + Pi forms ATP : energy production by oxidation of : lipids, carbohydrates, proteins and alcohol
ATP is broken down by energy usage

Question 7

what is the official SI unit for food energy

Answer 7

KJ (kilojoule)

1kcal= 4.2 kilojoules

Question 8

what nutrients do we require and why

Answer 8

carbs- supplies energy
protein-energy and essential AA
fat- energy and essential fatty acids 
minerals-essential
vitamins- essential 
minerals and vitamins are micronutrients 
water-hydration 
fibre-for normal GI function

Question 9

what are the major dietary carbs

Answer 9

starch-polymer of glucose
sucrose-glucose +fructose 
lactose - galactose +glucose
fructose 
glucose 
maltose-glucose+glucose 
glycogen-polymer of glucose

Question 10

what are the essentials amino acids

Answer 10

isoleucine 
lysine 
threonine 
histidine 
leucine 
methionine 
phenylalanine 
tryptophan 
valine

Question 11

what AA do children and pregnant women require in their diet

Answer 11

arginine
tyrosine
cysteine

Question 12

why are fats important to the diet

Answer 12

contain much less oxygen than carbs/proteins so more reduced and yield more energy when oxidised
required for absorption of fat soluble vitamins(A,D,E &K)
provide essential fatty acids: linoleic and linolenic acid

Question 13

why are minerals important to the diet

Answer 13

electrolytes establish ion gradients across membranes and maintain water balance
calcium & phosphorus are essential for structure(bones +teeth)
act as enzyme co-factors
iron essential for haemoglobin

Question 14

why can’t we digest cellulose

Answer 14

don’t have the enzyme required to break the β-1,4 linkages in cellulose

Question 15

what does the daily energy expenditure consist of

Answer 15

basal metabolic rate
voluntary physical activity
diet-induced thermogenesis

Question 16

define BMR and which hormone is it mainly controlled by

Answer 16

measure of basal energy required to maintain life-the functioning of the various tissues of the body at physical, digestive and emotional rest.
thyroid hormones

Question 17

why is BMR lower for women

Answer 17

women have more adipose tissue that is less metabolically active than lean muscle tissue

Question 18

what can increase BMR

Answer 18

hyperthyroidism
pregnancy
lactation

Question 19

define obesity

Answer 19

excessive fat accumulation in adipose tissue which impairs health
BMI of over 30

Question 20

State the different classes in BMI index

Answer 20

<18.5 underweight 
18.5-24.9 desirable weight 
25-29.9 overweight 
30-34.9 obese 
>35 severely obese

Question 21

what is marasmus and how does it present

Answer 21

type of protein-energy malnutrition 
most common in children under the age of 5
child looks emaciated 
signs of muscle wasting and loss of body fat
no oedema 
hair is thin and dry 
diarrhoea is common 
anaemia may be present

Question 22

what is kwashiorkor and how may it present

Answer 22

occurs in a young children who have been displaced from breastfeeding and are fed a diet with some carbohydrate and low protein content.
child is apathetic, lethargic and anorexic
pitting oedema
hepatomegaly and/or ascites (accumulation of fluid in peritoneal layer) cause abdomen to distend
serum albumin low
insufficient AA to make proteins decreasing oncotic (protein) pressure, increasing net flow of fluid from capillaries to the interstitium by Staling’s law of the capillary resulting in oedema

Question 23

what is refeedinging syndrome

Answer 23

rapid refeeding of energy rich foods in starved or inadequately nourished patients will rapidly increase blood sugar and insulin resulting in glycogen, fat and protein synthesis.. these processes use phosphate, magnesium and potassium from body stores that are already depleted. this causes electrolyte abnormalities like hypophosphatemia.