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Biology S3 > nutrition in humans > Flashcards

nutrition in humans Flashcards

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1
Q

y do organisms require food

A
  • growth,
  • for repair or replacement of worn and damaged tissues,
  • as a source of energy
  • to maintain health
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2
Q

how does food help in organism growth

A

food provides the substances needed for synthesising new protoplasm, cells and tissues

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3
Q

how does food help in being a source of energy

A

food has chemical potential energy.
when digested food is oxidised during respiration, the energy from the food is released in the form of ATP molecules.

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4
Q

what is ATP used for

A
  • (anabolism) chemical reactions that build complex molecules from simpler molecules
  • activities such as movement
  • maintenance of body temperature
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5
Q

3 components that make up food

A

nutrients
fibre
water

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6
Q

what are nutrients

A

nutrients are chemical substances in food that nourish the body.

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7
Q

what are the 5 groups of nutrients

A

carbohydrates
fats
proteins
minerals
vitamins

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8
Q

which 3 groups of nutrients are required in large qwuantities as they supply energy and materials to make new protoplasm

A

carbohydrates
fats
proteins

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9
Q

which 2 groups of nutrients are required in small qwuantities as they are needed to maintain normal metabolism. they have no energy value

A

minerals
vitamins

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10
Q

what elements are carbohydrates made up of

A

carbon
hydrogen
oxygen

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10
Q

what are the 3 main groups of carbohydrates

A

monosaccharides (simple sugars)
disaccharides (complex sugars)
polysaccharides

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11
Q

monosaccharide structuring

A

(C H2O) -> general formula
they tend to have 3,5 or 6 carbon atoms
C6H12O6 -> 6 carb atoms 6 waters

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12
Q

monosaccharide examples

A

glucose
fructose
galactose
they all have C6H12O6

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13
Q

monosaccharide functions

A
  • monosaccharide are the chief source of energy in the form of ATP during cellular respiration
  • form nucleic acids(DNA) as ribose sugar(backbone of nucleic acid) is a monosaccharide
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14
Q

disaccharides structures

A

is made up of two molecules of monosaccharides(simple sugars) joined together.
this is a condensation process involving the loss of water with the resulting establishment of a covalent bond called a glycosidic bond
glucose + monosac -> disach + water

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15
Q

disaccharides examples

A

sucrose
lactose
maltose

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16
Q

disaccharides functions

A

can become monosaccharides aka a source of energy when it is hydrolysed.
disach + water -> glucose + monosac
breaking a disach into 2 monosach is called hydrolytic reactionn which invloves water

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17
Q

polysaccharides structures

A

consists of many monosaccharide molecules joined togetyher. this is called polymerisation

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18
Q

polysaccharides examples

A

starch
glycogen
cellulose

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19
Q

polysaccharides functions

A
  • starch is a storage of carbohydrate in plants. it also hydrolyses to become a source of energy from glucose units.
  • glycogen is a compact storage of carbohydrate in animals
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20
Q

y is glycogen and starch both ideal storage materials

A

-they are insoluble in water(do not change the osmotic pressure in the cell)
-large molecules(cannot diffuse thru the cell membrane)
- they can be broken down to glucose molecules
- they have compact shapes(occupy less space)

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21
Q

what elements are fats made of

A

carbon
hydrogen
oxygen
(although the same as carbohydrates it contains less oxygen in proportion to hydrogen compared to carbohydrates)

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22
Q

what is a fat molecule made up of

A

4 molecules
1 glycerol attached to 3 long molecules, fatty acids

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23
Q

so what is obtained when fat is hydrolysed

A

fatty acids and glycerol
fat molecule + 3 H2O –lipase–> glycerol + 3 fatty acid

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24
Q

what grp is fats under/ i think is interchangeable with

A

LIPIDS
but if u thought nutirents kudos

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25
Q

lipids(fats) functions

A
  • forms part of the **cell membrane*
  • efficient source of energy that can be oxidised in respiration to CO2 and H2O, liberating 2x as much energy in the form of ATP as compared to the same weight in carbohydrates
  • long term storage
    -insulating material beneath the skin, prevent excessive heat loss
  • solvent for fat-soluble vitamins
  • protect vital organs
  • sebum, oily secretion, form on the skin restricting water loss
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26
Q

difference between animal fats and plant fats

A

animal fats are saturated fats
plant fats are unsaturated fats

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27
Q

what elements are proteins made of

A

carbon
hydrogen
oxygen
NITROGEN
sometimes sulfur and phosphorus are also present

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28
Q

what are the simpler compounds that proteins are made from

A

amino acids

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29
Q

protein functions

A

when proteins r digested, amino acids are absorbed into the bloodstream, enter the cells and used to build up different proteins such as,
-> proteins that form part of the protoplasm of new cells(growth) and worn-out cells(repair)
->enzymes of cells
->membrane proteins embedded in phospholipid bilayer
->actin and myosin in muscles
->keratin in hair and nails
->peptide hormones, insulin
-> antibodies that defend the body

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30
Q

what is kwashiorkor?????

A

its a protein deficiency disease

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31
Q

what are minerals?

A

minerals are inorganic salts which DO NOT provide energy but are required for normal, healthy development

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32
Q

what are some of the minerals needed in large amts

A

calcium
phosphorus
chlorine
sodium
potassium
iron
cancerous potatoes can sometimes poison infants

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33
Q

what are trace elements

A

trace elements are minerals needed in minute quantities such as
iodine
zinc
manganese

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34
Q

calcium function in the body

A

-in the form of calcium phosphate, is deposited in the bones and teeth making it hard
-present in blood plasma, essential in normal blood clotting
-chemical changes -> muscles contract.

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35
Q

iron fucntion in the body

A

-RBC contains haemoglobin. haemoglobin contains iron and it plays an important part in carrying oxygen around the body
-Mucle cells contain myoglobin. myogllobin contains iron and it plays an important role in storing oxygen in the muscle cells
-iron is needed for enzyme systems in all the body cells

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36
Q

what is anaemia

A

when a person is iron deficient. insufficient haemoglobin is made and the oxygen-carrying capacity of blood is reduced.

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37
Q

iodine function in the body (small amts)

A

it forms an essential part of the hormone thyroxine in the thyroid gland in the neck. deficiency in idoine lesads to goitre, swelling the neck.

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38
Q

phosphorus function in the body (small amts)

A

js to form calcium phosphate of bone and teeth, and also for ATP and DNA molecules.

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38
Q

what are the 2 grps of vitamins

A
  • fat-soluble vitamins (A,D,E,K) can be stored in the body
  • water-soluble vitamins (B,C) cannot be stored, daily intake needed
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39
Q

what are vitamins?

A

grp of organic substances that have these features:
- not digested or broken down for energy
- not built into body structures (used chemically)
- essential in very small quantities or normal health
- needed for chemical reactions in cells

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40
Q

**vitamin C (ascorbic acid) functions

A

-needed for formation of connective tissues that bind and support other tissues
-necessary for maintaining healthy epithelial tissues
-acts as an antioxidant

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41
Q

what causes scurvy

A

lack of vitamin C results in scurvy
swollen bleeding gums, poor healing wounds, bleeding under skin

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42
Q

where does excessive vitamin C go

A

excreted in urine

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43
Q

**vitamin D (calciferol) functions

A
  • promotes absorption of calcium and phosphorus compounds from the intestines
  • helps in deposition of calcium salts in the bones and teeth
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44
Q

how can we get vitamin D from sunlight

A

natural fats in the skin are converted to vit D.

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45
Q

what happens when vitamin D defiency

A

tooth weak, bone weak

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46
Q

vitamin A(retinol) function

A
  • needed for formation of light sensitive-pigment in the retina and for maintaining healthy epithelial tissues.
  • carotene from carrots is converted into vita A
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47
Q

deficient in vita A =

A

poor night vision, dry opaque cornea of eyes

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48
Q

What, in the plants, are we unable to digest

A

the cellulose in the cell walls of plants

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49
Q

what is fibre or roughage

A

the cellulose in the cell walls of plants

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50
Q

if fibre or roughage cant be digested how isit removed

A

it makes it to the large intestine and is egested in the faeces

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51
Q

fibre functions in the digestive tract

A

-prevents constipation
the fibre itself + the bacteria that feeds on it, adds bulk to the shit and helps it retain water. this softens the shit and and shit can come out easy
- fibre stimulates peristalsis
food moves thru the canal because of peristalsis, wavelike muscular contractions of the walls of the digestive tract. soft food does not stimulate the muscles but are by harder substances like fibre.

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52
Q

water functions in living things

A
  • essential part of cytoplasm
    water is the best known solvent. hence it serves as
  • a medium in which various chemicasl reactions of an organism occur in, eg, hydrolysis
  • a transporter of digested food,salts,vitamins,hormones,excess salt and urea
  • a major component of body fluids, blood, lymph and tissue fluiid
    HELPs to regulate the body temperature, sweating
    -esential reactant in photosynthesis
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53
Q

what is a balanced diet

A

a balanced diet consist of the right amt of carbohydrates, fats,proteins,vitamins,minerals,water and roughage to meet the daily reqs of the body

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54
Q

what must a balanced diet contain

A

enough
- carbohydrates and fats to meet our energy needs
- protein of the right kind to provide the essential amino acids to make new cells and tissues for growth and repair
- vitamins, dissolved mineral salts, fibre and water

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55
Q

Energy for each food

A

the amt of energy that can be obtained from food is measured in kilojoules or kilocalories
- 1g of carbohydrates -> 16kJ of energy
- 1g of fats -> 37kJ of energy
- 1g of proteins -> 17kJ of energy

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56
Q

what is basal metabolism

A

it is the amt of energy needed to carry on vital life processes when the body is in complete rest.
energy to maintain circulation, breathing, body temperature, brain function, essential chemical process in the liver and other organs
(aka base power needed)

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57
Q

what is basal metabolic rate

A

the amount of energy a person completely at rest uses per unit time

58
Q

what does total energy intake have to be sufficient for

A

total energy expenditure
- basal metabolism
- meet the needs of work and other physical activitties
- offset energy lost in heat

59
Q

what is enegry balance

A

when the total energy intake balances the total energy expenditure

60
Q

what affects the amt of energy we need each day

A
  • climate
  • body size
  • age
  • gender
  • health conditions
  • activity
61
Q

how does climate affect amt of energy we need each day

A

more energy is required in colder climates
- a person living in colder climates loses more heat ot the surroundsing compared to one living in the tropics, so more energy is required to maintain body temperature. basal metabolic rate is higher.

62
Q

how does body size affect amt of energy we need each day

A

A smaller body size has a higher metabolic rate than a bigger size.
- the smaller the animal, the greater the energy cost of maintaining a stable body temperature beacuse of a greater surface area to volume ration and thus a greater loss of heat to the surroundings

63
Q

how does age affect amt of energy we need each day

A

growing children have higher basal metabolic rates than adults

64
Q

how does gender affect amt of energy we need each day

A

men usually have higher heat production than women of the same body size and age because men tend to have more muscle tissue than fatty tissue, and muscle tissue uses up more energy than fatty tissue

65
Q

how does health conditions affect amt of energy we need each day

A

there is insufficient thyroxine from an underactive thyroid gland and excessive thyroxine from an overeactive thyroid gland. Thyroxine is a hormone thaty increases metabloc rate
Hence less thyroxine = less energy needed
More = more needed
(thyroxine is the neck thing that needs iodine)

66
Q

how does activity affect amt of energy we need each day

A

a person who does hard, manual work requires more energy in the form of ATP molecules for muscular activities than one who sits in an office.

67
Q

what are the 3 main world food supply related problmes

A

starvation, malnutrition and over-nutrition

68
Q

what is starvation

A

starvation occurs when a human does not receive enough energy from the diet.
to meet basic metabloic needs, the body uses energy reserves(fats, glycogen) when depleted proteins are used
msucles made of protein, muscle wasting

69
Q

what is malnutrition

A

malnutirtion results from dietary imbalance. due to dificiency or and excessive intake of a component of food

70
Q

what is over-nutrition

A

overconsumption of food than required by the body (for its energy needs or for building tissues) resulting in storage the surplus as fat.
-> leads to obesity

71
Q

special dietary needs for a pregnant woman

A

a pregnant woman needs to increase her intake of some substances
- protein-rich food (milk, eggs, beans) promotes rapid foetal tissue growth
- vegetables rich in folic acid promote development of the nervous system
- milk is a good source of calcium for one growth
- red meat is a good source of iron necessary for haemogloin the blood

72
Q

what does a lactating mother need

A

increased intakes of
-proteins,
-vitamins
-calcium

73
Q

what is nutrition

A

the intake of food and the processes that convert food substances into living matter are called nutrition

74
Q

what do growing children up to the age of 12 years require the following extra food substances

A
  • proteins for making new tissues
  • iron for haenmoglobin in red blood cells
  • carbohydrates as a source of energy in the form of ATP
  • calcium for growing bbones
  • vitamin A for disease resistance
  • vitamin D to help calcification of bones
    piccAD
75
Q

5 nutrition processes

A

ingestion
digestion
absorption
assimilation
egestion

76
Q

ingestion meaning

A

the intake of food into the body

77
Q

digestion meaning

A

the process whereby large, complex food molecules are broken down to smaller, simple, soluble and diffusible molecules so that they can be absorbed into the bloodstream

78
Q

absorption meaning

A

the passage of digested food materials through the walls of the small intestine into the bloodstream so that they can be carried to living cells in all parts of the body

79
Q

assimilation meaning

A

the process whereby some of the absorbed food materials are converted into new protoplasm or used to provide energy

80
Q

egestion meaning

A

The passing out of undigested food as faeces

81
Q

how do mammals feed

A

Mammals feed by ingesting complex, insoluble organic nutrients in their food which they digest into smaller and soluble molecules.

82
Q

what is holozoic nutrition

A

a specific form of heterotrophic nutrition where it basically means digesting solid food

82
Q

does digestion take place in the body cells?

A

no, digestion is extracellular. the nutrients then go back in

82
Q

the entrie alimentary canal

A

(i) Mouth and buccal cavity
(ii) Pharynx (throat)
(iii) Oesophagus (gullet)
(iv) Stomach
(v) Small intestine (duodenum, jejunum and ileum)
(vi) Caecum and appendix
(vii) Large intestine (colon and rectum)
(viii) Anus

82
Q

y is the alimentary canal so long

A

its atcl abt 900 cm long 🤓, it fits by coiling. the long alimentary canal gives the food enough time to be digested and absorbed into the body

83
Q

theres alot of gaps(abdominal cavity), so how do the organs js like float.

A

The gut is suspended from the wall of the abdominal cavity by tough connective tissue called mesentery that carries blood vessels, nerves and lymphatics that serve the gut.

84
Q

what r the 4 layers of the gut wall

A
  1. Serous coat (serosa) outer-most layer
  2. Muscular layer (muscularis mucosa)
  3. Submucous coat (submucosa)
  4. Mucous coat (mucosa) inner-most layer
85
Q

whats the Serous coat (serosa)

A

Serous coat (serosa) is an outer covering of loose connective tissue.

86
Q

whast the Muscular layer (muscularis mucosa)

A

Muscular layer (muscularis mucosa) is made up of two layers of smooth muscles which are responsible for peristalsis (slow, sustained and coordinated contractions), which propel food along the gut
- Outer layer of longitudinal muscles that run along the length of the canal
- Inner layer of circular muscles that run round the canal

87
Q

whast the Submucous coat (submucosa)

A

Submucous coat (submucosa) is made up of connective tissue and blood vessels

88
Q

whats the Mucous coat (mucosa)

A

Mucous coat (mucosa) is the innermost layer that is folded extensively. It contains cells that line the inside of the canal, forming an epithelium that secretes mucus.
Functions of mucus:
- It lubricates the food so that it moves more easily along the gut.
- It protects the lining from attack by digestive enzymes which are released into the alimentary canal.

89
Q

3 accesory organs(not in the gut but related to it)

A

(i) Salivary glands
(ii) Liver and gall bladder
(iii) Pancreas

89
Q

what is antagonistic muscle action in peristalsis

A

The two sets of muscles work in such a way that when one contracts, the other relaxes. This is known as antagonistic muscle action.

(i) When the circular muscle contracts, the longitudinal muscle relaxes.
–The gut constricts (lumen becomes smaller), i.e. it becomes narrower but longer.
 The food is squeezed and pushed forward.

(ii) When the longitudinal muscle contracts, the circular muscle relaxes.
–The gut dilates (lumen becomes larger), i.e. it becomes wider but shorter.
 The hollow lumen of the gut is widened for food to enter.

90
Q

what is peristalsis

A

The two layers of smooth muscles cause rhythmic, wave-like contractions of the walls of the gut. Such movements are known as peristalsis and they help to move food along the gut.

91
Q

what is chemical digestion

A

breaking down of large molecules (proteins, starch, fats) in food into smaller molecules. This involves hydrolytic reactions catalysed by digestive enzymes.

92
Q

what is physical digestion

A

breaking up of food into small particles mechanically.

93
Q

MOUTH AND BUCCAL CAVITY Structure
not super impt

A

 Food enters the body via the mouth which leads to the buccal cavity.
 The buccal cavity contains the muscular tongue, and is supported by the fixed upper and movable lower jaws in which the teeth are set in sockets. The jaws bear four types of teeth: incisors, canines, premolars and molars.
Three pairs of salivary glands open into the buccal cavity via ducts.

94
Q

teeth function in the mouth, mastication

A
  • solid food is broken up into small pieces by the grinding action of the teeth
  • physical digestion
  • Mastication reduces food to small particles, increasing the surface area on which enzymes act. Mastication also facilitates swallowing.
95
Q

tongue function in the mouth

A

The tongue rolls the food into small, slippery, spherical masses or boli (sing. bolus).

96
Q

salivary glands function in the mouth

A

Food in the mouth stimulates the salivary glands to secrete saliva.

97
Q

whats found in saliva and its function

A

(i) Mucus which helps to lubricate and soften the bolus for ease of swallowing
(ii) Salivary amylase (ptyalin) which catalyses the hydrolysis of cooked starch to maltose (chemical digestion)
(iii) Lysozyme which reduces bacterial contamination

98
Q

whats the pharynx

A

The pharynx is a common passage for food and air.

99
Q

During swallowing, what occurs to prevent food from passing into the trachea

A

(i) The larynx moves up.
(ii) The opening into the trachea (glottis) is partly closed by the contraction of a ring of muscles.
(iii) (epiglottis) flap covers the glottis.
the whole thing is the larynx, then it shifts upwards + ring of musdcle contract = epiglotiss flap cover

100
Q

whats the OESOPHAGUS

A

The oesophagus is a straight, narrow, thick-walled muscular tube that leads from the pharynx to the stomach.

101
Q

OESOPHAGUS adaptations

A

 The glands of submucosa secrete copious quantities of mucus into the lumen(empty space), lubricating the passage of the bolus.
 The bolus is propelled down the oesophagus towards the stomach by a wave of muscular contraction and relaxation known as peristalsis.

102
Q

STOMACH Structures

A
  • distensible muscular bag with thick and well-developed muscular walls.
  • lining of the stomach (mucous coat) has numerous pits, the walls of which are lined with gastric glands that produce gastric juice.
  • pyloric sphincter is a circular band of muscle at the lower end of the stomach which stops solid pieces of food from passing through.
103
Q

what does gastric juice contain

A

HCL, pepsin and rennin

104
Q

HCL function in the stomach

A

 Stops the action of salivary amylase
Kills germs and potential parasites in the ingested food
 Initiates conversion of inactive form of pepsin (pepsinogen) into pepsin
 Initiates conversion of inactive form of rennin (prorennin) into rennin
 Provides an acidic medium for the action of gastric enzymes

105
Q

what does pepsin do

A

catalyses the hydrolysis of proteins into short polypeptides or peptides.

106
Q

what does Rennin do

A

commences the digestion of milk proteins by
converting soluble CASEINOGEN protein -> insoluble CASEIN protein
the casein is then digested by pepsin

107
Q

so theres so much chemical warfare in the stomach, hows it not getting digested?

A

Mucus-secreting cells in the gastric glands secrete mucus that protects the stomach lining and glands from self-digestion (autolysis) by pepsin, which could lead to stomach ulcers.

108
Q

what is chyme

A

regular, peristaltic movements of the stomach(churning) mixes up the food and gastric juice into a semi-liquid known as chyme

109
Q

SMALL INTESTINE Structure

A

 The human intestine is about 5 – 6 metres long. There are two main regions: duodenum and ileum. In humans a zone intermediate between the duodenum and ileum, the jejunum, is identified.

110
Q

where does most absorption of digested nutrients, i.e. simple sugars, amino acids, fatty acids and glycerol, and water all take place

A

SMALL INTESTINE
STARPLAYER KING SMALL INTESTINE

110
Q

what does pancreatic juice contain

A

Pancreatic juice contains sodium hydrogencarbonate (which partly neutralises the acidic chyme) and the enzymes pancreatic amylase, pancreatic lipase and trypsinogen.

110
Q

what does the duodenum do

A

 The duodenum receives bile from the gall bladder and pancreatic juice from the pancreas(from the pancreatic duct)

110
Q

how is sodium hydrogencarbonate similar to bile

A

they are alkaline, so they neutralise the acidic chyme and provide a suitable medium for the action of pancreatic and intestinal enzymes.

111
Q

Fat digestion in the small intestine

A
  • bile is this green watery shit cuz of bile pigments that are formed from the breakdown of haemoglobin in the liver.
  • it contains no enzymes but it has bile salts tat emulsify fats, which means to break fats up into fat globules tat greatly increases the surface area to speed up digestion from pancreatic lipase.
  • emulsified fat is hydrolysed by pancreatic lipase to fatty acids + glycerol
111
Q

where is bile made

A

the liver, but stored in the gall bladder

111
Q

where are brush borders found and whats in the brush border

A

The microvilli of the epithelial cells lining the villi of the small intestine have these enzymes bound to them: enterokinase, peptidases, sucrase, maltase and lactase. They are called brush border enzymes.

112
Q

Carbohydrate digestion in the small intestine

A

starch digestion strats in the mouth but only a little, nothing in the stomach
ENTER SMALL INTESTINE:
 the remaining starch is hydrolysed into maltose by pancreatic amylase(found in p juice from pan to duodo)
 maltose is hydrolysed to 2 glucose by maltase
 lactose is hydrolysed to glucose and galactose by lactase
 sucrose is hydrolysed to glucose and fructose by sucrase

113
Q

Protein digestion in the small intestine

A

it starts in the stoimach
ENTER SMALL INTESTINE:
- trypsinogen from pan juice is converted to trypsin by enterokinase in the brush border. larger polypeptides that reach the small intestine are hydrolysed by trypsin to smaller (shorter) polypeptides.
- The smaller polypeptides or peptides (2 – 3 amino acids) produced are further digested to amino
acids, the end-products, by peptidases.

114
Q

5 adaptations of te small intestine for ABSORPTION OF NUTRIENTS

A
  1. LONG -> sufficient TIME -> large TOTAL SURFACE AREA
  2. many VILLI -> increase TOTAL SURFACE AREA
  3. epithial lining ONE CELL THICK -> SHHORTEN diffusion distance
  4. microvilli -> increase the surface area to volume ratio of one epithelial cell -> more brus border enzymes for digestion and carrier proteins
  5. dense network of BLOOD CAPILARRIES +LACTEAL -> transport away te nutrients -> maintain a steep concentration gradient of nutrients
  6. epitelial cell MANY MITOCHHONDRIA -> release energy IN FORM OF ATP during respiration -> ACTIVE TRANSPORT to absorb nutrients
115
Q

2 different modes of transport across the epithelial cells:

A

Passive diffusion down a concentration gradient from the lumen of the intestine into the epithelial cells for fructose, glycerol and fatty acids
Active transport against a concentration gradient for glucose, amino acids, galactose and dissolved mineral salts

116
Q

Two common types of lipoproteins

A

low density lipoproteins: LDLs contain 55% cholesterol.
high density lipoproteins: HDLs contain 21% cholesterol

117
Q

Absorption of simple sugars and amino acids

A
  • simple sugars and amino acids enter the blood capillaries and are carried away from the villi.
  • The capillaries join up to form veins and these veins unite to form the hepatic portal vein that leads directly to the liver. The liver plays an important role in regulating the level of nutrients in the blood, especially glucose.
118
Q

Absorption and transport of fatty acids and glycerol

A

fatty acids and glycerol enter the blood capillaries of the villi. but they recombine/condense to form fats again
fats mix with cholesterol and coated with proteins in epi -> lipoproteins droplets callked chylomicrons
passed into lacteal -> mix w colourless lymph -> milky chyle

119
Q

major function of the large intestine

A

absorb water and dissolved mineral salts. The undigested material is stored temporarily in the rectum before it is discharged as faeces through the anus. The removal of undigested material from the body is called egestion or defaecation.

120
Q

assimilation meaninhg

A

The products of digestion are carried around the body in the blood. From the blood, cells absorb and use glucose, fats and amino acids. This uptake and use of food is called assimilation.

120
Q

secondary active transport of glucose/galactose

A

sodium/glucose transporter takes up glucose / galactose against its concentration gradient by coupling its transport
-> facilitated diffusion into blood stream

121
Q

how does glucose become energy

A

 Glucose is oxidised to carbon dioxide and water during cellular respiration. This process releases energy in the form of ATP molecules

121
Q

how fructose enter the epithelial cell

A

it enters the epi cell via facilitated diffusion
-> facilitated diffusion into blood stream

122
Q

what hhappens to Amino acids which enter the cells

A

Amino acids which enter the cells are condensed into proteins,

123
Q

insulin function

A

 increasing permeability of cell membrane to glucose
->increasing the rate of glucose uptake by cells via facilitated diffusion
 stimulating the condensation of excess glucose to glycogen for storage in liver and muscles
increased oxidation of glucose during respiration
 promoting conversion of carbohydrates to fats

123
Q

whhats deamination?

A

excess amino acids r deaminated. thhe amino grp (N2) is removed -> form ammonia -> canged to urea -> excreted by kidney via urine
carbon-containing compound is leftover -> used for aerobic metabolism -> ATP or converted to glucose-> stored as glycogen in the liver and muscles.

123
Q

3 associated vessels to the liver

A

 the hepatic portal vein which brings digested food substances from the gut
 the hepatic artery which brings oxygenated blood and nutrients to the liver from the heart
 the hepatic vein which brings deoxygenated blood from the liver back to the heart

123
Q

what do thhe beta () cells of the islets of Langerhans in the pancreas do

A

The beta () cells of the islets of Langerhans in the pancreas detect the high blood glucose concentration and secrete the hormone insulin.

124
Q

wat happens when blood glucose level rises above 160 mg per 100 cm3 blood,

A

excess glucose is excreted by the kidneys in urine. This is known as diabetes mellitus.

124
Q

wat happens when blood glucose level may fall below 80 mg per 100 cm3 blood.

A

The glycogen store in the liver is broken down to glucose. This is stimulated by the hormone glucagon, secreted by the alpha () cells of the islets of Langerhans in the pancreas.

124
Q

what can liver cells do

A
  • convert excess carbohydrates to fats
  • remove cholestrol from blood and breaking it down
  • hydrolysis of fats into fty acid + glycerol
124
Q

wat happens when blood glucose level may fall below 40 mg per 100 cm3 blood.

A

the brain cells are adversely affected, leading to coma.

125
Q

what happens to old rbc

A

rbc gets engulfed by macropphages and releases haemoglobin
globin is the protein part and its broken down to its amino acids
iron in the heme is taken out and stored in the liver and reused.
The remaining part of the heme molecule -> biliverdin -> bilirubin, a yellowish pigment that becomes part of bile, a substance produced by the liver.

126
Q

wat does liver do to hormones

A

The liver is the primary site for the absorption and recycling of hormones. Steroid hormones such as the sex hormones (oestrogen and testosterone), insulin, glucagon, adrenaline and thyroid hormones are degraded in the liver.

127
Q

cirrhosis of the liver causesd

A

High doses of alcohol may lead to cirrhosis of the liver, a disease in which liver cells are damaged and replaced with fibrous tissue.

127
Q

effects of alcohol consumption on the brain

A
  • slows down the function of the brain and nervous system. Electrical signals take a longer time to travel to or from the brain.
  • self-control is reduced.
  • increases the reaction time

Biology S3 (6 decks)

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