orginisation - Topic 2 Flashcards
What does the digestive system do?
Breaks down carbohydrates, proteins and fats into smaller, soluble molecules so they can be absorbed into the blood.
What does bile do?
-neutralizes acid from the stomach (alkaline)
- emulsifies fats (helps break big blobs of fat by breaking them into smaller pieces which gives them a larger surface area for digestive enzymes such as lipase to work on)
Factors that impact enzyme activity
Temperature and PH
What would happen if enzymes were placed in the wrong conditions?
The active site will change meaning that the enzyme is denatured and can no longer break down the substrate.
What are enzymes?
Biological catalysts that help break down large insoluble molecules into smaller soluble molecules so that they can diffuse into the bloodstream.
What is the lock and key theory?
Enzymes work on specific substrates. The shape of the substrate must be complementary with the shape of the active site in order to form an enzyme- substrate complex.
Where is bile produced and stored?
Produced in the liver and stored in the gallbladder.
Where is amylase (carbohydrase) produced and what does it do?
Produced in the salivary glands, pancreas and small intestines. Acts on starch to produce glucose.
Where is lipase produced and what does it do?
Produced in the pancreas and small intestines. Acts on fats to produce glycerol and fatty acids.
Where is protease produced and what does it do?
Produced in the stomach, pancreas and small intestines. Acts on proteins to produce amino acids.
Factors increasing diffusion
- increase the surface area
- decrease the diffusion distance
- maintain a concentration gradient
What is the test and colour change for reducing sugars?
Benedict’s test
blue- green/yellow/orange/red
What is the test and colour change for non- reducing sugars?
Iodine test
brown/orange - blue/black
What is the test and colour change for protein?
Biuret’s test
Blue- lilac/pink
Name three types of tissue
- muscle tissue
- epithelial tissue
- glandular tissue
What is the function of the mouth?
-mechanically breaks down food
-mixes food with saliva which contains amylase to break down starch
What is the function of the stomach?
mixes the food with acid and enzymes to break it down
-contracts muscular walls to push food around and mix with acid and
-produces pepsin (protease enzyme)
-produces hydraucloric acid (kills bacteria and give the right ph for protease to work)
What does the liver do?
- produces bile
-filters the blood in the body and break down poisonous substances such as alcohol
What does the large intestine do?
-absorbs excess water and salts from undigested foods into the body which leaves behind feces
-producing and absorbing vitamins
-get rid of waste products as feces (stored in the rectum until removed)
What does the pancreas do?
-produces enzymes to break down sugars, fats, starches and protein
pushes these enzymes into the small intestine in the form of pancreatic juices
What does the small intestine do?
-breaks down food
-absorbs digested food into the bloodstream
- gets rid of any unnecessary components
-produces digestive enzymes to aid digestion (lipase, amylase,sucrase,lactase, maltase, aminopeptidase, carboxypeptidase)
How is the small intestine adapted for absorption?
-long (5m), provides a very large surface area for absorption of the product of digestion
- villi and microvilli increase surface area (more absorption at a quicker rate)
- very good blood supply so bloodstream rapidly removes the products of digestion and increases the concentration gradient
- thin membrane, short diffusion distance
-mitochondria, any molecules which cannot be absorbed by diffusion are absorbed by active transport
What is the function of the alveoli?
-site of gas exchange
-expand during inhilation (taking in oxygen)
-shrink during exhalation (expeling carbon dioxide)
What is the function of the diaphragm?
contracts and relaxes to pull air into the lungs
What is breathing?
The process of moving air in and out of the lungs
What is respiration?
The chemical reaction that releases energy from glucose usually in the presence of oxygen.
What is gas exchange?
The exchange of gases between the alveoli and blood in the capillaries by the process of diffusion
describe the order of the respiratory system
When we breathe in, air passes down our trachea (windpipe) which then divides between our two bronchi, and from there further divides between the bronchioles. Eventually, the air reaches the alveoli which will then be diffused into the bloodstream by a process called gas exchange.
Describe how the blood moves through the heart and around the body
- Blood is carried to the heart through the vena cava (de-oxygenated)
- Blood moves through the right atrium to the right ventricle (de-oxygenated)
- Blood is pumped through the pulmonary artery to the lungs (de-oxygenated)
- Blood returns to the heart through the pulmonary vein (oxygenated)
- Blood moves from the left atrium to the left ventricle (oxygenated)
- Blood is pumped to the rest of the body via the aorta (oxygenated)
Name the 8 parts of the heart organ
- pulmonary arteries (de-oxygenated)
- vena cava (de-oxygenated)
- right atrium (de-oxygenated)
- right ventricle (de- oxygenated)
- aorta (oxygenated)
- pulmonary vein (oxygenated)
- left atrium (oxygenated)
- left ventricle (oxygenated)
Function of arteries
Take oxygen-rich blood away from the heart and to the body
function of veins
return oxygen-poor blood to the heart
Function of cappilaries
Where substances are exchanged between the blood and other organs for example:
-oxygen in the lungs
-digested foods in the small intestine
-oxygen and nutrients are exchanged for carbon dioxide and waste
Describe the arteries
- high pressure
- thick walls
- narrow lumen
- no valves
- thick layer of muscle to make them strong and elastic fibres to allow them to stretch and spring back
Describe the veins
- low pressure
- thin walls
- wide lumen (help blood flow despite low blood preassure)
- contains valves (prevent backflow)
- capillaries join to form veins
What 4 main components is blood made up of ?
- Plasma
- Platelet
- White blood cells
- Red blood cells
Properties of plasma:
- transports hormones and digested food products
- a yellow liquid
-carries red and white blood cells, glucose and amino acids, co2, urea (from the liver to the kidneys), proteins, antibodies and antitoxins produced by the white blood cells.
Properties of white blood cells:
- can ingest pathogens (phagocytosis)
- defend against disease
- produce antibodies (fight microorganisms)
- produce antitoxins (neutralise any toxins produced by the microorganisms)
- have a nucleus
properties of platelets
-no nuclei
-important for clotting
-helps heal wounds
properties of red blood cells
-biconcave disc shape (large surface area more room for oxygen)
- contains haemoglobin (binds to oxygen)
- carries oxygen
-no nuclei (more room for oxygen)
-contains lots of iron
Function of the flower in a plant
attract pollinators and contains the reproductive system
Function of the leaf in a plant
absorbs light for photosynthesis
Function of the roots in a plant
absorbs water +mineral ions and anchors the plant
Function of the stem in a plant
supports the plant and is involved in the transport of substances to other parts of the body e.g. water
How are water and mineral ions transported into the plant?
water is moved into the root hair cell by osmosis whilst mineral ions such as nitrates are moved in by active transport
function of epidermal tissues
cover the plant, protecting it and preventing loss of water. this layer is often transparent to allow for sunlight to pass through.
Function of palisade mesophyll
where photosynthesis occurs. contains cells packed tightly together with high numbers of chloroplasts for photosynthesis to take place.
Function of the spongy mesophyll
layer has lots of air spaces for diffusion of gases
Function of waxy cuticle in plant
helps to reduce water loss
Function of stomata
small holes often on the underside of the leaf that allow for the diffusion of gases into and out of the leaf
Function of guard cells
either side of the stomata allows it to open and close to regulate the movement of gas + water
What happens to a plant when it is hydrated?
the guard cells become turgid which increases the size of the stomata allowing more gases to diffuse
What happens to a plant when it looses water by osmosis?
Guard cells become flaccid causing the stomata to close to conserve more water
What is translocation?
The movements of dissolved sugars via the phloem
Properties of the phloem
made up of living cells which are elongated and hollow to allow for the movement of substances in all directions (transloction) contains pores
Properties of xylem
composed of hollow tubes strengthened by lignin adapted for the transport of water via the transpiration stream from the roots throught the xylem and out of the leaves (transpirartion). the cells that make up the xylem are dead cells.
What is transpiration?
the process by which water is lost (evaporates) from a plants surface via the stomata.
the uninterrupted stream of water and solutes which is taken up by the roots and transported via the xylem to the leaves where it evaporates into the air
What is the transpiration stream?
the movement of water from the roots up to the leaves.
Factors affecting transpiration
-temperature (when its warm the particles gain energy and evaporate and diffuse so the warmer it is the faster transpiration happens)
-humidity ( the drier it is around the leaf the quicker transpiration happens if the air is humid then there isnt a big concentration difference so water wont diffuse)
-air flow (the better the air flow the greater the transpiration)
- light intensity (stomata close in the dark so the greater the light the greater the transpiration rate)
Function of the gallblader
-stores and releases bile into the small intestine
What is a catalyst?
a substance which increases the speed of a reaction, without being changed or used up in the reaction.Catalysts work by providing an alternative reaction route of lower activation energy.
at what ph do enzymes usually work best?
7 however pepsin works in the stomach at Ph 2 which means it is well suited for acidic conditions.
what is pepsin?
Pepsin is anaspartic proteasethat acts in the digestion of food proteins into smaller peptides and performs about 20% of the digestive function in the mammal stomach.
how to calculate rate of reaction
rate of reaction=change/time
What is the function of the pleural membranes?
to allow optimal expansion and contraction of the lungs during breathing.
How do the alveoli carry out gas exchange?
The blood in the cappilarry surrounding the alveoli has come back from to the lungs from the rest of the body which means it contains a high concentration of carbon dioxide and a low concentration of oxygen.Oxygen then diffuses from the high concentration in the alveoli to the low concentration in the blood and is carried around the body. opposite is for co2.
What happens to the oxygen in the blood once it reaches body cells?
oxygen is released from the red blood cells (where there is a high concentration) and diffused into the body cells (where there is a low concentration)
At the same time, co2 is diffused out of the body cells into the blood and then carried back to the lungs for gas exchange.
What blood does the right ventricle pump and where?
- de- oxygenated
- to the lungs to take in oxygen
What blood does the left ventricle pump and where?
- oxygenated
- all aaround to other organs in the body
- gives up its oxygen to the body cells and returns to the heart to be pumped out to the lungs again
Why does the heart have valves?
to make sure that blood flows in the right direction and prevent backflow
What are the sinoatrial nodes?
a group of cells in the right atrium wall that act as a pacemaker. they produce a small electric impulse which spreads to the surrounding muscle cells, causing them to contract
DEscribe the capillaries
-arteries branch into capillaries
- tiny
- thin wall and carry blood very close to every cell in the body (one cell thick) (exchange substances)
- very small lumen
- nucleus of cell
-permeable walls (substances can diffuse in and out)
- supply food and oxygen and take away waste like co2
rate of blood flow =
volume of blood/ number of minutes
What is urea and where is it produced and stored?
Urea (also called carbamide because it is a diamide of carbonic acid) isa waste product that is filtered out of the blood as it is poisonous. Urea is produced from the breakdown of excess amino acids in the liver.
Why is there a constant transpiration stream?
there is more water in the leaves than outside which means that water from in the leaves diffuse out through the stomata and is then evaporated. the evaporation causes a slight loss of water so more water is transported into the leaf through the xylem vessels to replace it.
How do you measure the rate of transpiration?
measure the uptke of water by a plant.
this is because you can assume that the water uptake of a plant is directly related to the water loss by the leaves (transpiration)
How would you measure the rate of transpiration in an experiment?
set up the potometer then record the starting position of the air bubble. start a stopwatch and record the distance moved by the air bubble per unit time. keep the conditions constant throughout the experiment.
Fill in the gaps:
when the plant has lots of water the guard cells fill with the water and become ______ and plump. this makes the stomata _____ so gases can be exchanged for ______________
when the plant has little water the guard cells lose water and become _______, making the stomata _____ this helps to stop water escaping
turgid
open
photosynthesis
flaccid
close
why are stomata usually found on the underside of a leaf?
the lower suface is cooler so less water is lost
How does increasing the temperature or PH cause an enzyme to denature?
the bonds that hold the enzyme together start to break so the active site changes shape
fill in the blank:
Starch is broken down by the enzyme_______into maltose molecules. These are then broken down further by_______into glucose.
amylase
maltase
Which substance are xylem cells reinforced with to make them stronger?
lignin
Enzymes are large proteins, so made from a long chain of______ acids.
amino
We now know that in order for an enzyme to catalyse a reaction, the enzymes active site actually changes shape slightly as it binds to the substrate.
What do we call this model of enzyme action?
the induced fit model
oxygen moves from the blood to the cells lining the stomach by _________
diffusion
what substance (other than oxygen) must move from the blood to the cells lining the stomach so that respiration can take place?
-glucose
-protein
-starch
starch
Food molecules such as protein cannot be absorbed unless they are digested. give one reason why
they are large and insoluble
Explain why PH affects enzyme activity
if the ph is too acidic then the active site of the enzyme will change and the enzyme becomes denatured. this means that it will no longer be able to bind with a substrate to form an (enzyme- substrate complex) and break down the substrate so enzyme activity will decrease.
describe and explain how the small intestines are adapted to maximise the rate of absorption of the products of digestion
The small intestines have many villi and microvilli. this increases the surface area which allows more diffusion of products into the bloodstream.
they also have thin walls which decrease the diffusion distance and increase the rate of diffusion.
villi contain lots of mitochondria, this means that any of the products that are not absorbed into the blood by diffusion, can use the energy from the mitochondria after respiration to absorb the products by active transport.
good blood supply - increase concentration gradient
What is a risk factor?
something that increases the chance of developing a diseas
Fill in the gaps:
Coronary _____ _________ is the build up of _______ __________ in the coronary ______ which narrows the _____ and _________ blood flow to the heart. this means that less _______ is recieved by the heart putting a strain on it which __________ the risk of _____ ______.
- heart disease
- fatty substance/ deposit
- artery
- lumen
- restricts
- oxygen
- increases
- heart attack
Name two treatments for coronary heart disease
- stent
-statins
What are statins?
a class of drug that can lower the level of LDL cholesterol in your blood and as a result reduce the risk of developing cardiovascular disease.
Name 3 advantages of using statins as a way to treat Coronary heart disease
- reduces LDL and increases HDL
- no surgery required
- less invasive than stents
- reduces risk of cardiovascular disease
Name disadvantages of using statins to treat coronary heart disease
- must be taken regularly and long term
- less effective if not taken regularly
- takes a while to start having an effect
- side effects such as muscle and joint pain, headaches, nausea
Name 4 risk factors for developing coronary heart disease/ cardiovascular disease
- age
- high blood pressure
- high LDL cholesterol
- Low LDL cholesterol
- overweight/ obesity
- diabetes
- smoking
What is a balanced diet?
a diet that includes all the correct proportions of the different food groups: carbohydrates, proteins, lipids, vitamins, minerals, dietary fibre, and water.
Name 3 factors that impacts how much energy you need per day and why?
Activity level- The more active you are the more energy you loose therefore the more energy you need to gain through eating
Age- Teenagers often need a lot of energy because they’re growing, whereas elderly people need less.
Pregnancy- Pregnant women need more energy because the baby growing inside them requires a lot of energy.
Name some main sources of carbohydrates
-sugars (fruit, fizzy drinks, sweets)
- starch (potato, rice, bread)
What is the function of protein?
growth and to repair body cells and tissues, including recovery after illness or injury.
Name some major sources of protein
Meat, eggs, cheese, beans, nuts and seeds
What is the function of lipids?
The body uses lipidsas an energy store, as insulation and to make cell membranes.
Name some sources of lipids
oils (liquid) and fats (solid).
-butter
-nuts
-fish
What is the difference between an oil and a fat?
oil is liquid at room temp but fat is solid at room temp
What is the function of vitamin A?
for growth, keeping the immune system healthy, and for good skin and eyesight
Name some sources of vitamin a
carrots, spinach, cabbage, liver
What is the result of a vitamin a defficiency?
vision loss, blindness
What is the function of vitamin c?
heal wounds by helping to form new connective tissue such as blood vessels, cartilage, muscle and collagen in bones
name some sources of vitamin c
citrus fruits (such as oranges, lemons and limes)
leafy green vegetables (such as sprouts and broccoli)
What does a vitamin c deficiency lead to ?
scurvy
Name 4 symptomns of scurvy
-bleeding and swelling of the gums,
-loss of teeth,
- tiredness
- muscle and joint pain.
What is the function of vitamin d?
help the body absorb calcium for strong teeth and bones.
name some sources of vitamin d
fish liver oils and fatty fish like tuna and salmon
What does a vitamin d deficiency lead to?
bone deformities such asrickets
What is the function of calcium?
to contribute to bone density and maintain healthy, strong teeth
what is the result of a calcium defficiency?
osteoporosis
sources of calcium:
yoghurt, leafy green vegetables, cheese, canned fish and milk
what i the function of iron?
prevent anaemia
how does iron prevent anaemeia?
Iron is needed to form hemoglobin, part of red blood cells that carry oxygen and remove carbon dioxide.
sources of iron:
red meat, liver, kidney, watercress
what is cancer?
the uncontrolled growth of cells which causes a lump called a tumor
What are the two types of cancer?
benign
malignant
What is benign cancer?
non cancerous. grows slowly and stays within a membrane. doesnt invade other tissue in the body.
What is malignant cancer?
cancerous. when the tumor grows and spreads to healthy neighbouring tissue. cells can break of and spread to other parts of the body through the bloodstream and then invade healthy tissue elsewhere in the body forming secondary tumours.
name 4 Risk factors and what cancer they link to
- smoking- lung, mouth, bowel, stomach, cervical
- obesity- bowel, liver, kidney
- uv exposure- skin
- viral infection- (hepatitis b and c increase risk of developing liver cancer)
