nutrition, respiration, gas exchange and transport Flashcards
how does peristalsis work
circular muscles and longitudinal muscles contract to produce wave like contractions which moves the food along
describe the digestion of starch
1) starch to maltose (by amylase)
2) maltose to glucose (by maltase)
where is bile produced and stored
produced in liver; stored in gall bladder
how is the small intestine adapted for absorption
1) very long
2) large surface area due to millions of tiny projections called villi
3) each cell on the surface of the villi has microvilli (increases sa more)
4) villi have a single permeable layer of surface cells to help quick absorption
5) very good blood supply + network of blood capillaries
6) lacteal for absorbing fats
symbol equation for aerobic respiration
C6H12O6+ 6O2-> 6CO2 +6H2O
word equation for anaerobic respiration in plants
glucose -> ethanol+ Carbon dioxide
word equation for anaerobic respiration in animals
glucose-> lactic acid
how is the structure of a leaf adapted for gas exchange
1) broad leaves= large surface area for diffusion
2) thin; short distance for gases to travel
3) air spaces inside the leaf; lets gases move easily between cells +increases sa
4) lower surface is full of stomata( tiny holes) which let water, oxygen and co2 in and out of the cells
describe the role of stomata in gas exchange
- they let gases diffuse in and out.
- at night they close since photosynthesis can’t happen in the dark.
- they close to stop water escaping so the plant doesn’t dry out
- they are controlled by guard cells; guard cells get bigger to open the stomata then get smaller to close them
describe the structure of the thorax
1) trachea
2) bronchi (2 tubes going into lungs
3) bronchi split into bronchioles
4) bronchioles end at alvioli
5) lungs, surrounded by pleural membranes
6) ribcage protects lungs
7) intercostal muscles run between the ribs
describe the role of the intercostal muscles and the diaphragm in ventilation
breathing in: diaphragm + external intercostal muscles contract (diaphragm flattens+ ribcage is pulled up); thorax volume increases; decreases pressure, drawing air in . Inverse for breathing out
how are alveoli adapted for gas exchange
1) huge number of microscopic alveoli gives lungs a huge surface area
2) moist lining for gases to dissolve in
3) thin walls (1 cell thick)
4) good blood supply- capillary network
5) permeable walls
describe how alveoli carry out gas exchange
1) high concentration of CO2 in blood, low concentration of O2
2) oxygen diffuses out of alveoli into blood and co2 diffuses out of blood into alveoli to be breathed out.
consequences of smoking
1) damages alveoli walls (reduces SA) leading to emphysema
2) tar damages cilia which makes chest infections more likely
3) tar irritates bronchi and bronchioles, producing excess mucus; leads to chronic bronchitis
4) carbon monoxide in smoke reduces amount of o2 carried in blood so heart pumps faster; increase in blood pressure damages artery walls, increasing risk of blood clots + coronary heart disease
5) carcinogens
role of the phloem
transports sucrose and amino acids between leaves and other parts
role of the xylem
transports water and mineral ions from roots to other parts
how is water absorbed by root hair cells
osmosis
what is transpiration
loss of water from the plant
what is the rate of transpiration affected by (and how)
1) light intensity: high light intensity = high transpiration (because stomata close in dark)
2) temperature: warmer=faster transpiration (more evaporation)
3) wind speed: high wind speed= high transpiration( creates constant concentration gradient)
4) humidity: high humidity= low transpiration (no concentration gradient)
describe the composition of the blood
- red blood cells
- platelets
- white blood cells
- plasma
what is the role of plasma
transports CO2, digested food, urea, hormones and heat energy
how are red blood cells adapted to transport oxygen
1) small+ biconcave shape: large SA for absorbing + releasing oxygen
2) no nucleus: extra space for carrying oxygen
3) contain haemoglobin: binds with oxygen in lungs then reverse in body tissues
how does the body respond to disease using white blood cells
1) phagocytes: ingest pathogens
2) lymphocytes: produces antibodies specific to the pathogen. Antibodies lock onto the pathogen’s antigen.
Also produce memory cells which remain in the body for the next time the same pathogen enters.
what is the role of platelets
platelets clump together to ‘plug’ the damaged area; they are held together by a mesh of protein called fibrin. prevents blood loss and entry of microorganisms
describe the structure of the heart
Right side: receives deoxygenated blood and pumps it to the lung
1)pulmonary artery (TO lungs)
2)vena cava (FROM body)
3) right atrium, semi-lunar valve, tricuspid valve and right ventricle.
Left side: receives oxygenated blood + pumps it to the whole body.
1) aorta (TO body)
2) pulmonary vein (FROM lungs)
3) left atrium, semi-lunar valve, bicuspid valve, left ventricle
4) thicker wall as needs to pump round the whole body
what does hepatic mean
to do with the liver
what does pulmonary mean
to do with the lungs
what does renal mean
to do with the kidneys
what factors increase the risk of coronary heart disease
- a diet high in saturated fats ( causes fatty deposits forming inside arteries)
- smoking (increase in blood pressure)
- inactive lifestyle
how are arteries adapted to their function
1) strong walls because the heart pumps blood out at a high pressure
2) elastic walls allow arteries to expand
3) thick, muscular walls compared to lumen to maintain high pressure
how are veins adapted to their function
1) thin walls because blood is at lower pressure going back to the heart
2) bigger lumen to help the blood flow
3) valves to keep the blood flowing in the right direction
how are capillaries adapted to their function
1) really tiny and carry the blood really close to every cell to exchange substances
2) permeable walls means eaasy diffusion
3) one cell thick walls
describe the structure and function of the human alimentary canal
-mouth: physically breaks down food
-Oesophagus: tube connecting mouth to stomach
-stomach: pummels food with muscular walls, produces pepsin and kills bacteria with Hcl
-small intestine (duodenum and ileum): produces protease, amylase and lipase; absorbs nutrients
large intestine: excess water absorbed(colon) ; faeces stored (rectum)
pancreas: produces digestive enzymes and secretes them to small intestine
what is magnesium needed for in plants
chlorophyll
what are nitrate ions needed for in plants
amino acids (growth)
how is a leaf adapted for photosynthesis
1) broad so large SA exposed to light
2) contain chloroplasts, found in the palisade layer (near the top where they get most light)
3) transparent upper epidermis so light can pass through
4) network of vascular bundles which deliver water and nutrients and take away glucose produced by photosynthesis
5) waxy cuticle prevents water loss
6) stomata + adaptations for gas exchange
symbol equation for photosynthesis
6CO2+ 6H20-> C6H1206 + 602
test for glucose
benedict’s test:
water bath
turns from blue to brick red if glucose present
test for starch
iodine:
brown to blue/black
test for protein
biuret:
blue to pink/purple
test for lipids
emulsion test:
mix in equal parts of alcohol and water,
milky white emulsion if lipid present
Why does a poor diet cause changes in number of blood cells
Iron is needed for haemoglobin which is in red blood cells
Why do athletes often live at High altitudes before competing in a long race
- more red blood cells;
- (more) oxygen;
- aerobic respiration;
- (less) lactic acid / (less) anaerobic respiration;
Why is having less white blood cells a risk
- (increase) risk of disease / infection;
- pathogen
- (fewer) lymphocytes;
- (fewer) antibodies;
- (fewer) phagocytes;
- (less) ingestion / engulfing / surrounding;
Vitamin a
vision/ sight in dim light;
Found in carrots
Lack of causes night blindness
Vitamin c
skin/ connective; tissue immune system
lack of causes scurvy
found in citrus fruits
Vitamin d
Bone growth
lack of causes rickets
found in dairy
Iron
Haemoglobin/ red blood cells
lack of causes anaemia/ fatigue
found in red meat
Dietary fibre
peristalsis / food movement
Found in fruit/veg
Lack of causes constipation
Elements in protein
hydrogen, oxygen, nitrogen and carbon. Some might also contain a fifth element, sulfur.
What is assimilation
Assimilation is the movement of digested food molecules into the cells of the body where they are used.
Describe a test to see if starch is present in a leaf
heat a plant leaf in boiling water for 30 seconds (this stops its chemical reactions)
heat it in boiling ethanol for a few minutes (this removes most of its colour) in water Bath/no naked flame
wash with water and spread onto a white tile
add iodine solution from a dropping pipette
How many chromosomes in a red blood cell
0- no nucleus
why are leaves in the shade thinner?
- cells nearer to surface so less
of a barrier - more light is absorbed
why does bubbling air through the water increase the uptake of mineral ions
oxygen is needed for respiration which gives energy for active transport
Function of mouth
Where food enters the alimentary canal and digestion begins
Function of oesophagus
Peristalsis
Function of stomach
Muscular organ where food is digested
Mechanical digestion through churning
Chemical digestion through enzymes
Function of Small intestine
duodenum = Where food is mixed with digestive enzymes and bile
Ileum = Where digested food is absorbed into the blood and lymph
Function of large intestine
- colon= Where water is reabsorbed
- rectum= Where faeces are stored
- anus= Where faeces leave the alimentary canal
salivary amylase
digests starch into maltose
produced by salivary glands
acts in mouth
pancreatic amylase
digests starch into maltose
produced by pancreas
acts in small intestine
maltase
digests maltose into glucose
produced by walls of small intestine
acts in small intestine
what is
a) starch
b) maltose
c) glucose
starch: polysaccharide
maltose: disaccharide (2 glucose molecules joined)
glucose: monosaccharide
pepsin
digests proteins into peptides
produced by stomach wall
acts in stomach
trypsin
digests proteins into peptides
produced by pancreas
acts in small intestine
peptidases
digests peptides into amino acids
produced by wall of small intestine
acts in small intestine
lipase
digest lipids into glycerol and 3 fatty acids
produced by pancreas
acts in small intestine
why does the stomach have a very low pH
HCL
kills bacteria , protecting us from food poisoning provide optimum ph for pepsin
role of bile
neutralise stomach acids and emulsify lipids
What is the role of memory cells
Recognise antigen, causing the immune response to be faster.
Antibodies are produced faster and more of them are produced
How do germinating seeds get energy
They have food stores containing carbohydrates
Carbohydrates are digested by enzymes to produce glucose for respiration
What are the conditions needed for germination (explain them)
Water: needed to activate enzymes for digestion
O2: needed for aerobic respiration/ active uptake
Temperature: high temp for enzymes (more kinetic energy so more collisions)
describe the adaptions of a root hair cell
shape: (long “hair” sticking out) gives larger surface area
how can you measure transpiration
use a potometer
cut a shoot under water
assemble the potometer and put the shoot in
make an air bubble by taking the tube out of the water
measure how long it takes for the bubble to move a certain distance
what colour is hydrocarbon indicator in different C02 conc
normal: orange
high: yellow
low: purple
why do plants need nitrates
making amino acids and proteins for cell growth. if a plant is deficient in nitrates it will have stunted growth and older leaves will turn yellow
why do plants need phosphates
contains phosphorus for making DNA and cell membranes needed for respiration and growth. deficiency will lead to poor root growth and purple leaves
why do plants need potassium
to help enzymes needed for photosynthesis and respiration. deficiency will cause poor flower and fruit growth and discoloured leaves
why do plants need magnesium
needed in small amounts to make chlorophyll. deficiency will cause yellow leaves
