Nutrition, Body Weight and Homeostasis Flashcards
(214 cards)
1
Q
Define metabolism
A
The chemical process that occur within living organisms in order to maintain life.
2
Q
What does metabolism consist of?
A
NAME?
3
Q
What do oxidative pathways do?
A
Convert food to energy
4
Q
What do fuel storage and mobilisation pathways do?
A
Allow food to be mobilised when we are not eating or need to increase energy
5
Q
How to fuel storage and mobilisation pathways allow fuel to be mobilised?
A
Through interconversion of glycogen and fat stores
6
Q
What do biosynthetic pathways do?
A
Produce basic building blocks for cells
7
Q
What do detoxification pathways do?
A
Remove toxins
8
Q
What are catabolic processes?
A
They break down molecules to release energy in form of reducing power
9
Q
What are anabolic processes?
A
They use energy and raw materials to make larger molecules for growth and maintenance
10
Q
Define energy
A
The capacity to do work
11
Q
What kind of energy to cells use?
A
Chemical bond energy
12
Q
How do cells use chemical bond energy?
A
Through the utilisation of ATP
13
Q
What kind of work do cells do?
A
NAME?
14
Q
What biosynthetic work do cells do?
A
Synthesis of cellular components
15
Q
What transport work do cells do?
A
Movement of ions and nutrients across membranes
16
Q
Why is the movement of ions across membranes important?
A
For neuronal communications
17
Q
What mechanical work do cells do?
A
Muscle contraction
18
Q
What electrical work do cells do?
A
Nervous conduction in the form of action potentials
19
Q
Where does osmotic work occur?
A
In the kidney
20
Q
Describe the structure of ATP
A
Adenine base linked to ribose sugar and 3 phosphates- alpha, beta and gamma.
21
Q
How does ATP release energy?
A
Bond between beta and gamma phosphate breaks
22
Q
Give the equation for ATP hydrolysis
A
ATP↔ ADP + Pi
23
Q
Give 5 examples something that pushes ATP hydrolysis in the forward direction
A
NAME?
24
Q
What pushes ATP hydrolysis in the backwards direction?
A
Energy production by oxidation
25
Give 4 examples of things oxidised for energy production
#NAME?
26
How is ATP generated?
By breaking down the chemical bonds in food
27
Give 3 processes that generate ATP
#NAME?
28
What is the official SI unit of energy?
kJ
29
How many kJ’s are there in 1 kcal (calorie)?
4.2
30
Give the 6 essential components of the diet
#NAME?
31
Which of the essential components of the diet can’t be digested?
Fibre
32
What are carbohydrates required for?
Mostly supply energy
33
What are proteins required for?
Energy and amino acids
34
When are proteins utilised for energy?
In starvation
35
What are fats required for?
Energy and essential fatty acids
36
What are minerals required for?
Cofactors of enzymes
37
What is water required for?
Hydration
38
What is fibre required for?
Normal GI function
39
Why can’t fibre be digested?
Because humans can’t digest the 1,4-ß glycosidic bonds in cellulose, as they don’t have the enzyme
40
Give 4 examples of carbohydrates
#NAME?
41
What is starch
A glucose polymer that is the carbohydrate storage molecule in plants
42
What are the monomers of sucrose?
Glucose and fructose
43
What are the monomers of lactose?
Glucose and galactose
44
What is the purpose of digestion of carbohydrates
To break larger carbohydrates into monosaccharides
45
Why must larger carbohydrates be broken down into monosaccharides?
So they can be absorbed in the blood
46
What are proteins composed of?
Amino acids in linear chains
47
How are amino acids in proteins linked?
Peptide bonds
48
What effect does digestion have on proteins?
Breaks them down into constituent amino acids
49
What happens to the amino acid products of digestion?
They are absorbed into the blood
50
How many amino acids are used for protein synthesis in the body?
20
51
How do amino acids differ from one another?
They each have a different side chain
52
How many essential amino acids are there?
9
53
Why are essential amino acids so called?
They cannot be synthesised by the body
54
What is the result of the inability of the body to synthesise essential amino acids?
They must be obtained from diet
55
How must protein hormones enter the body
Injected
56
Why must protein hormones be injected?
Otherwise the body would break them down
57
What are the 9 essential amino acids?
- Isoleucine
- Lysine
- Threonine
- Histidine
- Leucine
- Methionine
- Phenylalanine
- Tryptophan
- Valine
58
What is meant by conditionally essential?
Some amino acids are only essential in extreme circumstances
59
When may amino acids be conditionally essential?
In children and pregnant women
60
Why might amino acids be conditionally essential in children and pregnant women?
High rate of protein synthesis as rapid growth rate
61
What 3 amino acids are conditionally essential in children and pregnant women?
#NAME?
62
What is the difference between protein of animal origin and plant origin?
Protein of animal origin ‘high quality’- contains all amino acids. Proteins of plant origin usually deficient in 1+ essential amino acids
63
What is the result of protein of plant origin being of lower quality?
Vegetarians need proteins from wide variety of sources
64
What are lipids composed of?
Triacylglycerols
65
What are triacylglycerols composed of?
3 fatty acids esterified to 1 glycerol
66
What are the 2 types of lipids?
#NAME?
67
What is the result of a double bond in a lipid?
Allows more flexibility
68
How do fats differ from carbohydrates or protein?
They have much less oxygen
69
What is the result of fats having less oxygen than carbohydrates or protein?
They are more reduced, so yield more energy when oxidised
70
What are fats required for?
#NAME?
71
What are the 4 fat soluble vitamins?
#NAME?
72
What are the two essential fatty acids?
#NAME?
73
What kind of constituent are minerals in the diet?
Microconstituent
74
What is the role of electrolytes in cells?
They establish ion gradients across membranes and maintain a water balance
75
Give an example of an electrolyte required in the body
Cl -
76
Why is Cl - required in the diet?
It is an essential electrolyte for sodium potassium ATPase, needed to establish ion gradients
77
Give two examples of macrominerals
#NAME?
78
What are macrominerals essential for?
Structure, e.g. bones and teeth
79
Other than structure, what is calcium important for?
Important signalling molecule
80
Give 7 examples of enzyme cofactors
#NAME?
81
Give an example of a process that requires an enzyme cofactor
Glutathione peroxidase, required to combat oxidative stress, requires selenium
82
What is iron essential for?
Component of haemoglobin
83
From high to low amount, how much of a mineral is needed?
Electrolytes → minerals → trace minerals → ultratrace
84
In what quantity are vitamins required?
Very small
85
Are vitamins fat or water soluble?
Can be either
86
What happens if someone has incorrect vitamin intake?
If too little, can get deficiency diseases
| Can also have vitamin excess
87
Give an example of a vitamin excess disease, and it’s effects
#NAME?
88
Give 4 examples of fat soluble vitamins
#NAME?
89
Give 10 examples of water soluble vitamins
- B1 (Thiamine)
- B12
- B6
- Biotin
- C
- Choline
- Folate
- Niacin
- Pantothenic acid
- Riboflavin
90
What disease is caused by a deficiency in vitamin A?
Xerophthalmia
91
What disease is caused by a deficiency in vitamin D?
Rickets
92
What is caused by a deficiency in vitamin E?
Neurological abnormalities
93
What is caused by a deficiency in vitamin K?
Defective blood clotting
94
What disease is caused by a deficiency in vitamin B1?
Benberi
95
What disease is caused by a deficiency in vitamin B12?
Anaemia
96
What diseases are caused by a deficiency in vitamin B6?
Dermatitis, anaemia
97
What is caused by a deficiency in biotin?
Alopecia, scaly skin, CNS defects
98
What disease is caused by a deficiency in vitamin C?
Scurvy
99
What is caused by a deficiency in choline?
Liver damage
100
What is caused by a deficiency in folate?
Neural tube defects, anaemia
101
What disease is caused by a deficiency in niacin?
Pellagra
102
What is caused by a deficiency in pantothenic acid?
Fatigue, apathy
103
What disease is caused by a deficiency in riboflavin?
Ariboflavinisis
104
What vitamins have an antioxidant role?
A and C
105
What antioxidant role do vitamins A and C have?
They are free radical scroungers
106
Give 4 examples of dietary fibres
#NAME?
107
What is dietary fibre essential for?
Normal GI function
108
Can dietary fibres be broken down by human digestive enzymes?
No
109
What is the recommended intake of dietary fibre?
18g/day
110
What is the consequence of low dietary fibre?
#NAME?
111
What is the result of high dietary fibre intake?
Reduced cholesterol
112
Why does a high dietary fibre intake reduce cholesterol?
Bile salts are secreted into the stomach, which requires cholesterol. Fibre absorbs bile salts, so if there is high fibre intake, more bile salts are absorbed, so less bile salts reabsorbed into liver. This means that more bile salts must be made, so more cholesterol used.
113
What is the advantage of lower cholesterol?
Lower risk of diabetes
114
Who publishes dietary reference values (DRV’s)?
SACN
115
What are DRVs?
A series of estimates of amount of energy and nutrients needed by different groups of the UK population
116
What is the reference nutrient intake (RNI)?
The level of protein, vitamins and minerals that would meet the needs of 97.5% of the population
117
When is the estimated average requirement (EAR) used?
For energy
118
What is the EAR?
The energy requirement for 50% of the group
119
What is the lower reference nutrient value (LRNI)?
The level that would be enough for 2.5% of the population- the majority need more
120
When is safe intake used?
When there is insufficient data
121
What do nutrient requirements depend on?
#NAME?
122
How are nutrient requirements established?
By review of scientific evidence and frequency distribution for groups
123
Are nutrient requirements applicable to individuals?
No- groups.
124
Give 4 things that daily energy requirements depend upon
- Age
- Sex
- Body composition
- Physical activity
125
What is daily energy expenditure equal too?
Basal metabolic rate + diet induced thermogenesis + physical activity level
126
What is the basal metabolic rate?
The energy used to keep the body going, e.g. for liver function, brain etc.
127
What is diet induced thermogenesis?
Energy required to process food
128
Give two examples of things required for the maintenance of cells
- Ion transport across membrane
| - Biochemical reactions
129
What percentage of the BMR is accounted for by the skeletal muscle?
30
130
What percentage of the BMR is accounted for by the brain?
20
131
What percentage of the BMR is accounted for by the heart?
10
132
What percentage of the BMR is accounted for by other organs?
20
133
Give 5 factors that affect BMR
#NAME?
134
How does body size affect BMR?
Depends on surface area
135
How does gender affect BMR?
It is higher in males
136
How does environmental temperature affect BMR?
It increases when it’s cold
137
How does endocrine status affect BMR?
It is increased in hyperthyroidism
138
How does body temperature affect BMR?
It increases by 12% per degree
139
What does energy required for voluntary physical activity depend on?
Intensity
140
What systems does voluntary physical activity increase energy demand for?
#NAME?
141
What happens to the heart and breathing rate with physical activity?
They increase
142
What does an increase in energy demand with activity reflect?
An increase in demand on skeletal muscle
143
Why does skeletal muscle require more energy with activity?
Skeletal muscle hydrolyses ATP to form cross bridges that underlie skeletal muscle contraction.
144
How does skeletal muscle contraction work?
Muscle contraction is determined by myosin in the thick filament and actin in the thin filament. Myosin head binds to thin filament, hydrolyses ATP (chops off gamma phosphate). Energy released used to change the myosin head, which draws the filaments over each other.
145
What is the very short term energy store?
Creatine phosphate
146
Where is creatine phosphate found?
In the muscles
147
How much creatine phosphate do the muscle contain?
A few seconds worth
148
What energy store is used for immediate use?
Carbohydrate stores
149
What form are the carbohydrate stores in?
Glycogen
150
What is the time scale for glycogen utilisation?
Minutes to hours
151
Where is glycogen stored?
Muscles and liver
152
Where are the long term energy stores?
Adipose
153
How much energy is stored in adipose?
About 40 days worth
154
Where does energy come from in emergency situations?
Muscle protein converted to carbohydrate
155
Why is muscle protein only used as an energy source in emergency situations?
The body wants to conserve muscle mass
156
What is the main difference in body composition between men and women?
Fat
157
What happens to body composition in obesity?
Not everything in body increases, just adipose tissue
158
What happens if energy intake = expenditure?
The body weight is stable
159
What happens if energy intake > expenditure?
Energy stores increase
160
What happens if energy intake
Body components, e.g. protein, utilised to provide energy
161
What is obesity?
Excessive fat accumulation in adipose tissues
162
What is the result of obesity?
It impairs health
163
How is obesity usually measured?
In BMI
164
What BMI would be considered obese?
Over 30
165
What is the problem with obesity?
It is the major preventable cause of death in developed countries, with an increasing prevalence
166
What health issues is obesity associated with?
- Increased risk of some cancers
- Cardiovascular disease
- Type 2 diabetes
167
What is the unit for BMI?
kg/m 2
168
How is BMI calculated?
Weight (kg) / Height 2 (m 2 )
169
What is BMI used for?
To clinically evaluate a patients weight
170
What BMI is considered underweight?
Under 18.5
171
What BMI is considered normal?
18.5 - 24.9
172
What BMI is considered overweight?
25 - 29.9
173
What BMI is considered severely obese?
Over 35
174
Under what conditions is BMI measured?
#NAME?
175
What is the advantage of a BMI measurement?
Good correlation with body fat measurement
176
What is the disadvantage of a BMI measurement?
Very muscular individuals may be classified as obese
177
What is an alternative to BMI?
Hip-to-waist ratio
178
What has been evidenced to be clinically important?
Distribution of body fat
179
Why is distribution of body fat clinically important?
Greater proportion of fat in upper body (especially abdomen) compared with hips is associated with increased risk of-
- insulin resistance
- hyperinsulinism
- type 2 diabetes
- stroke
- hypertension
- hyperlipidaemia
- premature death
180
What is a major preventable cause of death in developing countries?
Malnutrition
181
What are the two main types of malnutrition?
- Kwashiorkor
| - Marasmus
182
What is kwashiorkor?
Protein deficiency
183
What is marasmus?
Insufficient energy
184
Why does malnutrition cause death?
Due to damage from low energy intake and deficiency diseases of other nutrients
185
What can low protein intake result in?
Insufficient blood protein synthesis
186
Why does low protein synthesis result in insufficient blood protein synthesis?
Inhibition of the liver to create proteins such as albumin
187
What is the result of insufficient blood protein production?
A decrease in plasma osmotic pressure and oedema
188
What is Starlings Law of the Capillary?
Flow net = (P c - P i ) - (π c - π i )
When
- P x = hydrostatic pressure
- π x = oncotic pressure
- X c = of capillary
- X i = of interstitial fluid
189
Using Starling’s Law of Capillary, what causes oedema?
π c decreases because of decrease in plasma protein, therefore increased net flow of fluid into interstitial fluid
190
What does fluid oedema lead to?
Distended abdomen
191
Give 6 functions of blood
- Transport
- Coagulation
- Immune functions
- Regulation of body pH
- Regulation of core body temperature
- Hydraulic functions
192
What are the transport functions of blood?
- O 2 and nutrient supply
- Removal of waste products
- Signalling
193
What are the nutrients supplied by the blood used for?
#NAME?
194
Give 3 waste products removed by the blood
- CO 2
- Urea
- Lactic acid
195
How is the blood used for signalling?
By transporting hormones
196
Why is metabolite measurement in the blood used rather than using actual tissue samples?
Difficult to examine actual tissues with metabolic problem, as could be dangerous or expensive to biopsy
197
What are the advantages of using blood to measure metabolite concentrations?
- Blood readily obtainable
| - Tests inexpensive
198
What could an increase or decrease in concentrations of substances found in blood mean?
Could be used as diagnostic tool to help indicate nature of problem
199
Give an example of where a change in concentration of substances in blood could be used as a diagnostic tool
An increase in ketone bodies could be indicative of diabetes
200
Are normal ranges of substances found in blood absolute or typical?
Typical - they vary within a range
201
What does the concentration of substances in the blood depend on?
#NAME?
202
What can happen when the skeletal muscle, liver and adipose tissue release the substances they store?
Can change the concentrations of nutrients in the blood plasma
203
Which organs can interconvert substances?
#NAME?
204
Which tissues can utilise nutrients?
All
205
What do homeostatic mechanisms do?
Act to counteract changes in the internal enviroment
206
Are body systems in a steady state?
No, in a dynamic equilibrium
207
What is the result of homeostatic failure?
Disease
208
What levels do homeostatic mechanisms exist on?
All- cell, tissue, organ, organism
209
Are homeostatic mechanisms independent or interdependent for the variable being regulated?
#NAME?
210
What are the 4 main aspects of a homeostatic mechanism?
#NAME?
211
What does the receptor do?
Monitors and responds to changes in environment
212
What does the control centre do?
- Sets range where variable is maintained
- Determines appropriate response
- Sends signal to effector
213
What does the effector do?
Brings about desired changes
214
What does negative feedback do?
Corrects deviation
