B8: Nutrition Flashcards
what is nutrition?
process by which living organisms obtain food
two types of nutrition are:
autotrophic and heterotrophic
autotrophic nutrition is carried out by:
- green plants
- some bacteria
- green algae
autotrophs make thier food by using this process
photosynthesis
different types of heterotrophic nutrition
- saprophytic nutrition - obtaining food from remains of dead organisms
- holozoic nutrition - one organism consumes another
- parasitic nutrition - parasites obtain food from their host and harm their host in the process
examples of saprophytes
- fungi
- most bacteria
examples of parasites
- tick and flees
- tapeworm in the intestines of humans
- ringworm in humans
- head lice
define photosynthesis
process by which green plants convert carbon dioxide and water into glucose using sunlight energy
(1)________ traps sunlight energy and is found in (2)__________
- chlorophyll
- chloroplasts
what is equation for phtosynthesis
6CO2 + 6H2O ====> C6H12O6 + 6O2
what happens in the light stage of photosynthesis?
- requires light energy
- Water molecules are split unto hydrogen and oxygen using the light energy absorbed by chorophyll in the choroplasts
- the oxygen gas is released as waste
what happens in the dark phase of photosynthesis?
- does not require light energy
- requires enzymes
- hydrogen produced in the light stage is used to combine with carbon dioxide to form glucose
the 2 stages of photosynthesis are(1)__________ and (2)___________. (1)______ requires (3)_________ and (2) requires (4)_________
- light stage
- dark stage
- light energy
- enzymes
which stage of photosynthesis does not require light?
light-independent stage or the dark stage
which stage of photosynthesis does not require enzymes?
light stage
what are the conditions needed for photosynthesis?
CLUE - use the equation for photsynthesis as a guide
- Carbon dioxide
- water
- sunlight energy
- chlorophyll
- enzymes
- suitable temperature
idenitfy the labelled parts of the internal structure of the leaf and indentify the cells that contain chloroplasts
- waxy cuticle
- upper epidermis
- palisade layer
- xylem
- phloem
- spongy mesophyl layer
- guard cells - chloroplasts
- spongy mesophyll cells - chloroplasts
- palisade cell - chloroplasts
- epidermal cell - no chloroplast
- waxy cuticle
- stoma
what is the function of each part?
- prevents dehydration of the leaf
- upper epidermis - protects the cells underneath
- palisade layer - where most photosynthesis takes place
- xylem - tubes that bring water to the leaf
- phloem - tubes that take water away from the leaf
- spongy mesophyl layer - allows for easy movement of carbon dioxide and oxygen
- guard cells - chloroplasts
- spongy mesophyll cells - chloroplasts
- palisade cell - closest to the sunlight and 900 to the leaf surface. Contains large amounts of chloroplast for photosynthesis
- epidermal cell - no chloroplast
- waxy cuticle - prevent water loss
- stoma - allow carbon dioxide to diffuse in and oxygen to diffuse out of the leaves
identify the parts of the leaf and state thier function/s
A - Lamina (leaf blade) - wide and flat for large surface area to volume ratio
B - main vein (midrib) - contains xylem and phloem for transport of substances
C - Net Veins - support the lamina and contain xylem and phloem for transport
D - Petiole (leaf stalk) - holds leaves at right angles to the sun. contains xylem, phloem for transport of substances between the leaves and plant
E - Lamina margin
how are leaves adapted for photosynthesis?
- lamina is broad and flat for large surface area to absorb sunlight and carbon dioxide
- lamina is thin for sunlight and carbon dioxide to reach all cells
- lamina lies at 90o to sunlight by the petioles to maximize exposure to the sunlight
- the laminae are spaced out around stems so ech can have maximum exposure to sunlight
- each lamina is held out flat by veins to maximise exposure to sunight
What are the environmental factors that affect the rate of photosynthesis?
Clue - these are 4 main abiotic factors
- light: greatly reduced rate at dusk and nights
- temperature: decreased rate during winter months where it is cold
- water decreased photosynthesis: decreased photosynthesis during the dry season and when the ground is frozen
- carbon dioxide: rate is limited during the day as concentrations of carbon dioxide concentration in the air is very low (0.04%)
explain the graph below regarding the limiting factors of photosynthesis
clue- identify the limiting factors
Explain each of the graphs below
Clue - identify the limiting factors in each case
what happens to glucose produce in photosynthesis?
- used by the plant for energy
- stored by the plant in form of starch
- converted to sucrose which is then used to make other substances such as:
- amino acids and protein by addition of nitrogen and sulfur
- cellulose for cell walls
- vitamins
- lipids which are stored mainly in seeds
Plants need minerals to make different compounds for proper growth and development. List the main minerals needed by plants and the form is which these are obtained
- nitrogen: nitrate ions
- magnesium: Magnesium ions
- phosphorous: phosphate ions
- potassium: potassium ions
- sulfur: sulphate ions
- calcium: calcium ions
what are the results on plants of deficiency of the minerals below?
- nitrogen
- magnesium
(1)deficieny of nitrogen:
- poor growth
- yellowing of leaves(chlorosis) especially older leaves
- few and underdeveloped leaves
- short roots
(2) deficiency of magnesium
* chlorosis especially of older leaves
what is hydroponics?
when plants are grown in water or sand and supplied with the minerals they require in solution
Identify the different structures in the diagram below
1-Mouth or buccal cavity; 2- salivary gland; 3-liver; 4-stmach, 5-pancreas, 6-duodenum, 7-ileum, 8-colon, 9-colon, 10-rectum, 11-anus, 12-appenix, 13-caecum, 14-pancreatic duct, 15-bile duct, 16-pyloric sphincter, 17-gall bladder, 18-diaphram, 19-oesophagus, 20- epiglottis, 21-teeth, 22-lips, 23-tongue
Identify the parts and regions of the tooth
A-crown, B-neck, C-root, 1-enamel, 2-dentine, 3-gum, 4-cement, 5-cement fibres, 6-pulp cavity, 7-blood vessel, 8-nerve
Identify the different types of teeth
I- incisor, C- canine, PM-premolar, M-molar, 1-incisor, 2-canine, 3-premolar, 4-molar
The 5 processes involved in human nutrition are -
- ingestion
- digestion
- absorbtion
- assimilation
- egestion
define digestion
process by which food is broken down into simple soluble food molecules that can be absorbed by the body
define absorbtion
the soluble molecules of digestion move into the body fluids and cells
define assimilation
the absorbed molecules are used by the cells for their different metablic processes.
define egestion
undigested food is expelled from the body
what are the two types of digestion?
- mechanical
- chemical
mechanical digestion is a (1)_________ process and begins in the (2)__________ with the (3)_________. Chemical digestion is a (4)____________ process where food is broken down by a process calles (5)________ and requires (6)____________
- physical
- mouth
- teeth
- chemical
- hydrolysis
- digestive enzymes
reasons for mechanical digestion
- makes food easier to swallow
- increase surface area of the food for digestive enzymes to act
how many diferent type of teeth do humans have?
4
How is food moved through the alimentary canal?
peristalsis
define peristalsis
the movement of food through through alimentary canal by contraction of the circular muscles behind the bolus of food.
what are the 3 main categories of enzymes and what is their role?
- carbohydrases - hydrolyse polysaccharides and disaccharides
- proteases - hydrolyse proteins
- lipases - hydrolyse own lipids
The products of hydrolysis of carbohyrates are (1)_________; of proteins are (2)______; of lipids are (3)_________
- monosaccharides
- aminoacids
- fatty acids and glycerol
chemical digestion begins in the(1)________ and ends in the (2)__________.
- mouth
- small intestine
say the category in which each enzyme belongs, where it is found and its source?
- salivary amylase
- rennin
- pepsin
- pancreatic amylase
- trypsin
- pancreatic lipase
- maltase
- sucrase
- lactase
- peptidase
- carbohydrase - saliva in mouth - salivary glands
- protease - gastric juice in stomach - cells of stomach wall
- protease - gastric juice in stomach - cells of stomach wall
- carbohydrase - pancreatic juice in small intestine - pancreas
- protease - pancreatic juice in small intestine - pancreas
- pancreatic lipase - pancreatic juice in small intestine - pancreas
- carbohydrase - intestinal juice - cells in the wall of small intestine
- carbohydrase - intestinal juice - cells in the wall of small intestine
- carbohydrase - intestinal juice - cells in the wall of small intestine
- protease - intestinal juice - cells in the wall of small intestine
what are the end products of the digestion of the following?
- starch
- protein
- lipids
- glucose
- amino acids
- fatty acids and glycerol
Properties of enzymes
- they are proteins
- each enzyme catalyses only one reaction
- they can be reused repeatedly
- activity is afected by temperature
- actvity affected by pH
what are the factors that affect enzyme acitvity?
- temperature
- pH
Increasing temperature (1)_______ enzyme activity until a temperature of about (2)__________, known as the (3)________ temperature, where enzyme activity is (4)_________. Above this temperature enzyme activity (5)________ rapidly and is zero at (6)_______ due (7)________ of the enzyme.
- increases
- 40 deg C
- optimum
- greatest
- decreases
- 60 deg C
- denaturization
interpret the graphs. what is the optimum pH of each enzyme?
enzyme acitivity increases with pH until optimum pH after which enzyme activity decrease to zero. each enzyme has its own pH range and optimal pH
optimum pH of pepsin is 1.5
optimum pH of Salivary amylase is 6.5
optimum pH of alkaline phosphatase is 9
list the main food test for the main food groups below
- Reducing sugars - monosaccharides such as glucose and fructose and some disaccharides such a maltose
- Non-reducing sugars - sucrose
- Starch
- Protein
- Lipids
- (i)Benedict’s test; (ii)Fehling’s test
- Reaction with HCl and NaOH
- Reaction with iodine solution
- Biuret Test
- (i)Ethanol test; (ii)grease spot test
how to test for reducing sugars (eg. glucose, fructose)
2ml of a solution of the suspected reducing sugar + 2ml Benedicts solution + gentle heat = colour change from blue to green to orange or red.
how to test for non-reducing sugars (eg. Sucrose)
- boil 1ml suspected sample with 1ml HCl which results in reducing sugars.
- add 1ml NaOH to neutralise the acid
- add 2ml Benedicts solution and heat gently
how to test for the presence of starch
add a few drops of iodine solution to sample of food. sample will turn blue-black
How to test for Lipids
- dissolve 2mls of sample of food in 2ml ethanol then shake to dissolve and then add water. a white suspension will appear when water added.
- Grease spot test. Rub food sample on paper and allow to dry. A transucent greasy spot remains
How to test for proteins
Biuret test: 2ml of biuret solution to 2ml of sample. sample turns from blue to lilac or purple
Sources of vitamin A
- Liver
- cod liver oil
- yellow and orange vegetables eg carrots and pumpkin
Sources of Vitamin B1
- Whole-grain cereals and bread
- brown rice
- peas
- nuts
- lean pork
- yeast extract
Sources of vitamin B3
- Lean meats
- fish
- whole-grain cereals
- yeast extract
Sources of vitamin C
- West indian Cherries
- citrus fruits
- raw green vegetables
Sources of vitamin D
- Oily fish
- cod liver oil
- eggs
NB Vitamin D is also made in the body by the action of sunlight on the skin.
Sources of calcium
- dairy products eg. milk cheese, yogurt
- green vegetables eg broccoli
Sources of phosphorus
- protein rich foods eg milk, cheese, meat , poulry, fish , nuts
Sources of iron
- Red meat
- Liver
- eggs
- beans
- nuts
- dark green leafy vegetables eg spinach
Sources of iodine
- sea foods eg fish , shellfish, seaweed
- milk
- eggs
Sources of sodium and potassium
1- Sodium
- table salt
- cheese
- cured meats
2- Potassium
- fruits
- vegetables
Sources of fluorine
- Fluorinated tap water
- fluoride toothpast
what causes beriberi?
Vitamin B1 deficiency
what causes Scurvy?
deficiency of vitamin C
what causes night blindess, dry skin
lack of vitamin A
what causes rickets
deficiency of vitamin D
what vitamin may be lacking in a person who is always tired, irritable, depressed and who has difficulty concentrating?
Vitamin B6
