B2 Flashcards
What are enzymes
Biological catalysts for chemical reactions
Protein molecules
Explain the lock and key theory
The active site will only bind to its specific substrate because they are complementary to eachother.
A chemical reaction then occurs of which molecule are broken down to produce smaller molecules
What is protease and where is it found
Enzyme that breaks down proteins
Stomach, pancreas, small intestine
Explain the digestion of proteins
Proteins are made up of ling chains on amino acids
When digested, protease enzymes break down proteins back into individual amino acids
Amino acids are then absorbed into bloodstream
After absorption they are joined back together in a different order to form human proteins
What is amylase and where is it found
Enzyme that breaks down starch
Found in salivary glands, pancreas, small intestine
what is a single circulatory system
blood passes through the heart once
what is the downside of a single circulatory system
blood looses its pressure and travels slowly - not giving efficient amount of oxygen
what is a double circulatory system in humans
blood passes through the heart twice for every circuit in the body
deoxygenated blood is pumped from the right side of the heart to the lungs and the oxygenated blood is pumped from the left side of the heart to the rest of the body
explain the pattern of blood flow
1.blood flows into the atria through the pulmonary vein and vena cava
2.the atria contract forcing blood into the ventricles
3.ventricles contract forces blood out the heart through the pulmonary artery and aorta
explain the digestion of starch
- starch consists of a chain of glucose molecules
- amylase enzyme breaks down starch into simple sugars
what is lipase and where is it found
Breaks down lipids
Found in pancreas and small intestine
explain the digestion of lipids
- lipid molecule consists of a glycerol molecule attached to 3 molecules of fatty acids
- lipase enzyme breaks down lipid molecule into glycerol and fatty acids
what is bile and where is it found
made in the liver and stored in gallbladder
Alkaline - neutralises HCL in stomach so that the small intestine enzymes can work t their best rate
Speeds up digestion of lipids but are not enzymes - emulsifies fats
explain the digestion of lipids by bile
bile converts large lipid molecules into smaller droplets
This increases the surface area of lipid which increases rate of lipid breakdown by lipase
what is the effect of temperature on enzymes
- As temperature increases, the rate of reaction increases as molecules have more energy + collisions
- The rate increases until it reaches the optimum temperature- where the enzyme activity is the fastest
- As the temperature increases past the optimum, the enzyme activity rapidly decreases to zero and so the enzyme denatures
what is the effect of pH on enzymes
- A pH too low or too high can lead to the enzyme being denatured
- An enzyme has a specific optimum pH and must stay that pH in order to work at its best rate
- Different enzymes have different optimum pHs
what are coronary arteries
- branch off the aorta and surround the heart
- provide oxygen to muscle cells of heart
- oxygen is used in respiration for contraction energy
what are pacemakers
resting heart rate controlled by a group of cells in the right atrium
Cells send electrical impulses which cause muscle contraction
Artificial pacemakers corrects any irregularities in the heart rate
what are the arteries and its structures
- carry blood away from the heart
- has thick, strong muscular walls to withstand high pressured blood
- have elastic fibres to allow them to stretch and recoil through blood surges passing through
- small lumen
What are the capillaries and its structure
- involved in the exchange of materials at the tissues
- very small and have tiny lumen
- carry blood very close to every cell to exchange substances
- Thin walls giving short diffusion path and increasing rate of diffusion
- Permeable walls
- supply food and oxygen to cells and take away waste eg. Co2
What are veins and their structure
- Carry blood back to the heart
- thin walls as the blood flows at low pressure and thick walls aren’t required
- valves to prevent back flow
- bugger lumen for better blood flow
how do you calculate the rate of blood flow
Rate of blood flow = volume of blood / no. minutes
what is the blood made out of
plasma
platelets
white blood cells
red blood cells
describe the plasma and its functions
- pale straw liquid which carries and transports material
- rbc/wbc and platelets
- soluble digestion products which are absorbed by small intestine
- carbon dioxide
- urea
- hormones
- proteins
- antibodies and antitoxins
What are platelets and its function
- small fragments of cells
- no nucleus
- help clot blood at wounds
What are red blood cells and their function
- carries oxygen from lungs to the rest of the body
- contain red pigment called haemoglobin
- no nucleus to allow more pace for haemoglobin
- biconcave disc which increases SA and more oxygen absorption
What is haemoglobin
Red pigment in rbcs which to bind to oxygen and carry it through the blood
What are white blood cells and their functions
- defend against infection ( immune system)
- engulf pathogens
- produce antibodies and antitoxins to neutralise Any toxins produced by pathogens
- have a nucleus
What causes the coronary heart disease
- when the coronary arteries blood flow gets blocked by the build up of fatty layers
- this causes the arteries to become narrow so blood flow is restricted and there is a lack of oxygen to heart muscle
- can result in heart attack
What are stents
- tubes that are inserted inside arteries to keep them open to ensure that blood can pass through
What are the pros of stents
- lowers risk of heart attack in people with coronary heart disease
- effective for a long time and recovery time is relatively quick
What are the cons of stents
- risk of complications during operation and risk of infection from surgery
- risk of blood clot near the stent (thrombosis)
What are statins
Drugs that can reduce the amount of bad cholesterol present in the bloodstream which slows down the rate of fatty deposits forming
What are the pros of statins
- Reduces risk of strokes, coronary heart disease and heart attacks 
- decreases the amount of bad cholesterol so the amount of good cholesterol increases meaning it can remove the bad cholesterol
What are the cons of statins
- long-term drug that should be taken regularly so risk someone would forget to take them
- negative side effects which could be serious
- The effect of statins isn’t instant it take time
What are artificial hearts and how it works
- Mechanical device that pump blood for someone who has heart failure
- usually used as a temporary fix to keep person alive until donor heart is found / to let heart rest and heal
What are the pros for artificial hearts
- less likely to be rejected by the bodies immune system
What are the cons for artificial hearts
- surgery can lead to bleeding an infection
- don’t work as well as healthy natural hearts
- increases risk of blood clots which can lead to strokes
- patient has to take drugs to thin the blood
What does a damaged valve cause
- valve can become stiff which can restrict blood flow
- valves can be leaky which allows backflow to happen meaning the blood doesn’t circulate as effectively as normal
What are the pros of mechanical valves
- can last a lifetime
What are the cons of mechanical valves
- increase the risk of blood clots
- Have to take anti clotting drugs
What are the pros of biological valves
- do not need to take drugs
What are the cons of biological valves
- don’t last long and may need to be replaced
- some are against it for ethical reasons
What is the definition of health
The state of physical and mental well being
What factors can affect your health
- poor diet
- high levels of stress
- lifestyle situations
What does a defective immune system cause you
You are much more likely to suffer from infectious diseases as your immune system is less likely to be able to fight off pathogens
What are some examples of interactive diseases
HPV - cervical cancer
Immune system reactions - allergies / asthma
Physical illness (eg arthritis) - mental health illness (eg depression)
What is epidemiology
Studying the pattern of disease to determine risk factors
Why is smoking a risk factor
- causes lung cancer/disease , cardiovascular disease and other types of cancer (bowel, mouth, stomach)
- contains chemicals which contain cancer called carcinogens 
What is a benign tumour
- where the tumour grows until there is no room
- do not invade any other parts of body
- non cancerous
What is the risk of drinking too much alcohol
- cause liver disease
- affect brain function
- damage nerve cells in brain
How is obesity a risk factor
- can cause type 2 diabetes by making the body less sensitive or resistant to insulin meaning there’s a loss of control concentration of glucose in blood
- can cause many cancers eg. Bowel liver and kidney
Function of waxy cuticle layer
Reduces water loss by evaporation
Function of upper epidermis
Transparent so that light can pass through to palisade layer
Function of palisade layer
- where most of photosynthesis happens
- contains lots of chloroplasts
- near the top of leaf where they can get the most light
Function of xylem and phloem
- form a network of vascular bundles which deliver water and other nutrients to entire leaf and take away glucose produced by photosynthesis
- help support the structure
Explain gas exchange in the leaf
- Carbon dioxide diffuses into air spaces in the spongey mesophyll through the stomata and then diffuses into palisade cells where photosynthesis happens
- Oxygen and water vapour diffuse out through the stomata
What is the function of stomata
Allows gases to diffuse in and out of cell
What is the function of the guard cells
Control the stomata and how much water is lost
Function of meristem tissue
Found at growing tips of shoots and roots and is able to differentiate into lots of different plant cells allowing plant to grow
