Studied by 30 people
Looks like no one added any tags here yet for you.
what elements r found in lipids (fats)?
carbon, hydrogen, oxygen
what is the structure of a lipid?
3 fatty acids + 1 glycerol molecule
what are oils?
plant lipids , liquid at room temp
what is the test for lipids?
add ethanol add water and shake positive result: milky white emulsion forms
what elements are found in proteins?
carbon, hydrogen, oxygen, nitrogen, sometimes sulfur
what are proteins made up of? (structure)
long chains of amino acids there are 20 different amino acids
give some examples of proteins found in the human body
collagen and keratin found in skin and nails all enzymes haemoglobin
what is the test for protein?
add Biuret reagent positive result = purple
what elements are found in carbohydrates?
carbon, hydrogen and oxygen
what is the test for glucose?
heat with water and Benedict's solution positive result: brick red
what are starch and glycogen made up of?
simple sugars (e.g. glucose) joined together
what is the test for starch?
add iodine positive result : turns blue/black
what is a monosaccharide?
a simple sugar, such as glucose or fructose
what is the general molecular formula for a monosaccharide?
C6H12O6
what is a disaccharide?
formed when two monosaccharides join together
what is maltose?
formed by two glucose molecules
what is sucrose?
formed from one glucose and one fructose molecule
what is a polysaccharide?
formed when lots of monosaccharides join together
provide some examples of polysaccharides
starch, glycogen and cellulose- formed when lots of glucose molecules join together
how do amino acid sequences change the function of the protein?
different proteins have different amino acid sequences different sequences = polypeptide chains fold in different ways every protein has a unique 3D shape that enables it to carry out its functiion
define enzyme
biological catalyst speeds up reaction without being used up
what is metabolism?
the rate at which chemical reactions take place in the body
what is a substrate?
a molecule an enzyme acts upon
what is the active site?
an area on an enzyme at which enzyme activity is fastest
what is the definition of 'optimum'
the temperature or pH at which enzyme activity rate is fastest
what does it mean for an enzyme to denature?
when an enzyme changes shape so substrate no longer fits active site
how does the lock and key mechanism work?
enzymes + substrates randomly move about in solution when an enzyme and its complimentary substrate collide, with the substrate fitting into the active site of the enzyme- an enzyme-substrate complez forms, and the reaction occurs a product/s forms from the substrate/s which are then released from the active site. the enzyme is unchanged and will go on to catalyse further reactions
describe and explain the effect of too high temp on enzyme activity
dec activity enzyme denatures and substrate can no longer fit the active site
why does dec the temp below the optimum dec enzyme activity?
lower kinetic energy fewer collisions between enzymes + substrates
why is it imp that we control our internal temp?
too high = enzymes denature too low = enzymes work too slowly (little kinetic energy) and cant catalyse chemical reactions fast enough
describe and explain the effect of too high or too low pH on enzyme activity
decreases activity enzyme denatures and substrate can no longer fit the active site
why is a balanced diet important?
helps maintain good health
give the consequences of having a diet that contains too much fat
obesity blockage of arteries high blood pressure / heart disease diabetes
outline the components of protein
role = growth/repair of muscles food rich in nutrient = meat, fish, eggs, cheese deficiency disease = kwashiokor
outline the components of carbohydrates
role = energy store food rich in nutrient = glucose - fruits and vegetables lactose - milk sucrose - table sugar starch - rice, potato, wheat
outline the components of lipids
role = insulation and long-term energy store food rich in nutrient = butter, cheese
outline the components of water
supports chemical reactions inside cells
outline the components of fibre
prevents constipation helps move food through gut food rich in nutrient = fruit and vegetables
outline the components of calcium
role = strong teeth and bones found in= milk and cheese
outline the components of iron
used to make haemoglobin food rich in = red meat deficiency disease = anaemia
outline the components of vitamin c
role = sticks together cells lining the mouth present in = citrus eg lemons + oranges lack of = scurvy (bleeding gums)
outline the components of vitamin a
role = good vision present in = fish liver oils, butter, carrots lack of = night blindness
outline the components of vitamin d
role = strong bones present in= fish liver oils, made by skin in sunlight lack of = rickets
how do energy requirements vary with activity levels?
age - older people need less food than young people as activity levels are lower pregnant women need more food, iron and calcium to support growing baby
why is food needed?
for growth and repair of tissues fight disease supply fuel needed to release energy
what is digestion?
the break down of large, insoluble molecules into small, soluble ones for absorption through the wall of the small intestine
what is mechanical digestion?
the physical breakdown of food eg. teeth chew food, muscles in stomach churn food
what is chemical digestion?
enzymes act as biological catalysts break down large, insoluble molecules into small, soluble ones
how does digestion start in the mouth?
mechanical breakdown of food by teeth amylase released - digests starch into maltose
what is peristalsis?
contraction and relaxation of circular and longitudinal muscles which push food along the gut
what is the role of the stomach?
secretes hydrochloric acid to kill pathogens muscular walls churn food (mechanical digestion)
what is the role of hydrochloric acid?
kill pathogens
what is the role of bile?
emulsifies - breaks down large lipid droplets into small ones to inc the surface area neutralises hydrochloric acid
where is bile made, stored and released into?
made - liver stored - gallbladder released into - small intestine
what is the effect of bile on lipids?
what is the role of maltase?
to digest maltose into glucose
what is the role of amylase?
to digest starch into maltose
where is amylase made?
salivary glands, pancreas
where does amylase act?
mouth, small intestine
what is the role of lipase?
to digest lipids into fatty acids and glycerol
where is lipase made?
pancreas
where does lipase act?
small intestine
what is the role of protease?
to digest proteins into amino acids
where is protease made?
stomach, pancreas
where does protease act?
stomach, small intestine
how is the small intestine adapted for its function?
large surface area provided by villi and microvilli
lots of capillaries
thin wall - short diffusion distance
lacteals -absorption of fats
what is the role of the rectum?
stores faeces
what is ingestion?
when food enters the mouth
what is absorption?
the movement of soluble food through the wall of the small intestine into the blood stream
what is assimilation?
when small food molecules are used to build large ones
what is excretion?
the removal of waste products of metabolism
what is egestion?
the removal of faeces from the anus
what is the word equation for photosynthesis?
carbon dioxide + water (+light energy0 —> oxygen and glucose
what is the balanced symbol equation for photosynthesis?
6CO2+6H20 —> 6O2 + C6H12O6
what is a limiting factor?
factor in a reaction which is in shortest supply
lack of this factor is the reason why the rate of reaction no longer increases
what are the limiting factors of photosynthesis?
carbon dioxide
light intensity
temperature
increasing any of the above will increase the rate of photosynthesis until another factor becomes limiting
why is the rate of photosynthesis low in the morning?
temperature is the limiting factor
low temperatures inhibit enzyme activitty
carbon dioxide levels are high
why is the rate of photosynthesis high at midday?
high temp maximises enzyme activity
co2 is the limiting factor as its in the shortest supply
how is the leaf adapted to their role?
thin and broad (large surface area)
why do chloroplasts appear green?
chlorophyll absorbs red/blue light
reflects green light
why do different coloured lights affect the rate of photosynthesis?
green is reflected (not absorbed) = low rate of photosynthesis
blue and red is absorbed - results in faster rate of photosynthesis
what does the plant use glucose for?
making cellulose cell walls
making proteins and DNA
making starch for storage
making sucrose for transport
what is the role of nitrate in plants?
making amino acids and proteins
making DNA
growth
deficiency symptom = stunted growth
what is the role of magnesium ions in plants?
making chlorophyll
deficiency symptom = yellow leaves
how is the waxy cuticle adapted for its role?
prevents evaporation of water and stops pathogen entry
how is th3 upper epidermis adapted for its role?
transparent to allow light to enter the leaf
how is the palisade mesophyll adapted for its role?
contains lots of chloroplasts for photosynthesis
how are the air spaces in spongy mesophyll adapted for their role?
allow gases to diffuse
how is the xylem adapted for its role?
allows entry of water and mineral ions by transpiration stream
how are the guard cells adapted for its role?
control opening and closure of stomata
how is the stomata adapted for its role?
allow co2 t0 enter, o and h20 to leave
Note
Flashcard