Topic 2 - Organisation Flashcards
Catalyst definition
A substance which increases the speed of a reaction without being changed or used up in the reaction
What are enzymes made up of
All large proteins - chains of amino acids
These chains are folded into unique shapes
Why enzymes have specific shapes?
Enzymes have an active site with a unique shape that fits substrate in reaction
Substrate has to match enzymes active site for reaction to be catalysed
Enzymes need right pH and temperature
Increasing temperature may increase rate of reaction initially but too high - enzyme denatures - loses shape
Same for pH
Amylase
Carbohydrase
Catalyses breakdown of starch to maltose
Made in: Salivary glands - pancreas - small intestine
Detection of Starch
Use iodine
Starch present - browny/orange to blue/black
Method for investing pH on enzyme activity
Put drop of iodine in every well in spotting tile
Heat water to 35°C and keep constant
Use syringe to add 1cm3 of amylase and 1cm3 of buffer with a pH
Put tube in beaker and wait 5mins
Add 5cm3 of starch
Record how long takes for starch breakdown by taking drop into spotting tile every 30seconds
Repeat with different pH’s
Proteases
Breaks down proteins into amino acids
Made in: stomach - pancreas - small intestine
Pepsin
Protease
Made in stomach
Works best at pH 2
Lipases
Converts lipids to Glycerol and Fatty acids
Made in: pancreas - small intestine
Bile
Produced in liver
Stored in gall bladder
Released into small intestine
Hydrochloric acid in stomach to low pH (acidic) for enzymes in small intestine
Bile is alkaline so neutralises acid to make conditions alkaline - optimum for enzymes in small intestine
Emulsifies fats - breaks into smaller pieces
Digestive system
Mouth - Salivary glands Oesophagus Stomach Liver Gall Bladder Pancreas Small intestine Large intestine Rectum
Salivary glands
Produce amylase
Stomach
Pummels food with muscular walls
Produces pepsin
Produces hydrochloric acid - kill bacteria - pepsin optimum pH 2
Liver
Bile produced
Bile - neutralises acid - emulsifies fats
Gall bladder
Where bile stored before released into small intestine
Pancreas
Produces protease - amylase - lipase
Releases to small intestine
Small intestine
Produces protease, amylase, lipase
Digested food absorbed into bloodstream
Large intestine
Where excess water absorbed from food
Benedicts test
Test for sugars
Do test in heated water bath
If sugar blue to green - yellow - brick red : depending on mass of sugar
Iodine test
Test for starch
Browny orange to black or blue/black
Biuret test
Test for proteins
Blue to pink/purple
Sudan III
Test for lipids
If lipids present mixture separate into 2 layers top layer - bright red
No lipids - no separate layer
Parts of lungs
Trachea Bronchus Bronchioles Alveoli Ribs Intercostal muscles Diaphragm
What happens at the alveoli
Blood passing alveoli has come from rest of body - lots of CO2 little oxygen
Oxygen diffuses out of alveoli into blood
Carbon dioxide diffuses out of blood into alveoli
Double circulatory system
Humans have a double circulatory system as two circuits
One pumps deoxygenated blood
One pumps oxygenated blood
Movement of blood
Deoxygenated blood - vena cava - right atrium - right ventricle - pulmonary artery - lungs - pulmonary vein - left atrium - left ventricle - aorta - rest of body
Coronary arteries
Supplies the blood with oxygenated blood
Branch off aorta and surround heart
Pacemakers
Resting heart rate controlled by group of cells in right atrium
Cells produce electric impulses that spreads to muscle cells making them contract
Artificial pacemaker
Device with wire to heart
Produces electric current so heart beats regularly
Arteries
Carry blood away from heart
High pressure
Walls thick layer of muscle - lumen small in comparison
Elastic fibres allow to stretch
Capillaries
Permeable one cell thick wall
Very small lumen
Supply food and oxygen - remove CO2
Veins
Lower pressure
Large lumen and narrow walls
Have valves to stop backflow of blood
Red blood cells
Biconcave disc
Large surface area
No nucleus
Red pigment - haemoglobin that binds to oxygen to become oxyhaemoglobin
White blood cells
Phagocytes - change shape to engulf pathogens
Lymphocytes - produce antibodies - to stop reproduction
produce antitoxins to neutralise toxins produced
Platelets
Small fragments of cells used to clot a wound
Plasma
Carries: Red + white blood cells; platelets; Hormones; proteins; Urea from liver to kidneys Carbon dioxide from organs to lungs Glucose and amino acids
Coronary heart disease
Coronary arteries get blocked by layers of fatty material
Arteries become narrow - blood flow restricted - lack of oxygen - heart attack
Stents
Tubes inserted inside arteries
Push artery wall out so more space for blood
Effective for long time; recovery from surgery quick
Risk of developing blood clot near splint - thrombosis
Cholesterol
A lipid body produces and needs to function properly
Too much of bad cholesterol causes health problems
Cause fatty deposits to form
Statins
Drugs that reduce amount of bad cholesterol in blood
Advantages of statins
Reduce risk of heart attack, strokes, coronary heart disease
Increase amount of good cholesterol which reduces amount of bad cholesterol
May prevent other diseases
Disadvantages of statins
Need to be taken regularly - long term
Some possible serious side effects - liver damage, kidney failure
Effect not instant
Artificial hearts
Artificial hearts that pump blood for patient
Less likely to be rejected by body’s immune system as not living tissue so not recognised as foreign
Disadvantages: Parts can wear out; electric motor may fail; blood doesn’t flow as smoothly - blood clots, strokes; patient needs to take drugs
Faulty heart valves
Can be damaged or weakened by heart attacks, infection, old age
Valve tissue may stiffen - wont open properly
May become leaky - blood flows both directions
Replacement valves
Biological valves - taken from humans or other mammals
Mechanical valves - man made
Artificial blood
Artificial blood is a blood substitute that can replace lost volumes of blood
Allows person to still pump remaining red blood cells around body
Ideally artificial blood could replace function of lost red blood cells - not possible yet
Health
State of physical and mental wellbeing
Communicable diseases
Can spread from person to person
Bacteria, viruses, fungi, parasites
Measles and malaria
Non-communicable diseases
Cannot spread
Generally last longer time - get worse slowly
Asthma, cancer, coronary heart disease
Examples of diseases that interact
Weakened immune system - increased chance of suffering from communicable diseases
Hepatitis virus - long term infections in liver - liver cancer
HPV - cervical cancer in woman
Factors affecting health
Balanced diet
Stress
Life situation - easy access to medicine, healthy food
Risk factors that increase chance of getting disease
Lifestyle - exercise and diet
Environment - air pollution
Developed countries - non communicable diseases more common - can afford to buy fatty food
Deprived areas - higher chance of smoking, poor diet, no exercise
Risk factors that cause disease directly
Smoking - damages walls of arteries and cells in lining of lungs - lung cancer + disease, cardiovascular disease
Obesity - body less sensitive to insulin - type 2 diabetes
Alcohol - liver disease + damages nerve cells in brain
Benign tumour
Tumour grows until no more room
Usually stays within membrane and doesn’t invade other tissues
Not cancerous
Usually not dangerous
Malignant tumor
Tumour grows and spreads to neighbouring healthy tissues
Cells break of and spread to other parts of body in bloodstream to form secondary tumours
Can be fatal
Cancerous
Risk factors for cancer
Smoking - linked to lung, mouth, bowel, stomach and cervical cancer
Obesity - bowel, liver and kidney cancer
UV exposure - skin cancer
Viral infection - hepatitis B and C - liver cancer
Genes - mutations in BRCA gene - breast and ovarian cancer
Examples of plant tissues
Epidermal tissues - covers whole plant
Palisade mesophyll tissue - where most photosynthesis happens
Spongy mesophyll tissue - in leaf, contains big air spaces to allow gases to diffuse in and out of cells
Xylem + phloem - transport water, mineral ions and food around plant
Meristem tissue - found at growing tips of shoots and roots, able to differentiate into different types of plant cell
Structure and Function of epidermal tissues
Covered with waxy cuticle - reduces water loss by evaporation
Upper epidermis is transparent - light can pass through to palisade layer
Structure and function of palisade mesophyll layer
Layer near top of leaf
Lots of chloroplasts to increase rate of photosynthesis
Structure and Function of lower epidermis
Contains lots of stomata surrounded by guard cells
Lets carbon dioxide directly diffuse into leaf
Guard cells control opening of stomata in response to environment
Structure and function of spongy mesophyll layer
Lots of air spaces to increase the surface area of cells - increases rate of diffusion of gases
Phloem
Made of columns of living elongated cells with small pores in end walls to allow cell sap to flow through
Transport food substances(mainly dissolved sugars) made in leaves to rest of plant to be used or stored
Transport goes in both directions
Process called translocation
Xylem tubes
Made of dead cells joined end to end with no end walls between them and hole down middle
Strengthened with material called lignin
Carry water and mineral ions from roots to stem+leaves
Movement of water from roots, through xylem and out of leaves called transpiration stream
Transpiration
Loss of water from plants
Caused by evaporation and diffusion from surface - mainly leaves
Evaporation in leaf means shortage of water in leaf - more water drawn from rest of plant in xylem - more water drawn up from roots
Means constant transpiration stream
Side effect of how leaves adapted for photosynthesis
Stomata allow gases to exchange easily
More water in plant than out
Diffuses to outside leaf
What affects transpiration
Light intensity - Stomata close when dark as don’t need to be open for photosynthesis so less water escapes. Higher light intensity more transpiration
Temperature - When warm water particles more energy to evaporate and diffuse out of stomata
Air Flow - Good air flow (stronger wind) more transpiration. More wind means diffused water vapour transported away from leaf so diffusion gradient stays high
Humidity - Drier air means faster transpiration. If air humid already water vapour in air so diffusion gradient low
How to estimate rate of transpiration
Measure uptake of water from plant
Can assume water uptake directly related to water loss
Use a potometer
Potometer - Apparatus where capillary tube runs from plant in water to a beaker of water. A bubble is in the capillary tube. Record how far bubble moves in mm over set time to find rate of water taken in - rate of transpiration
Guard cells
Kidney shape
When plant has lots of water the guard cells fill with it and become turgid - makes stomata open so gases exchange for photosynthesis
When plant short of water - guard cells lose water - flaccid - stomata close - stops too much water vapour escaping
Thin outer walls and thickened inner walls make opening and closing work
Sensitive to light and close when dark (at night) to save water
More stomata on underside of leaf because the lower surface is shaded and cooler so less water is lost
