Organisation Flashcards
Cells
Basic building blocks that make up all living organisms
Tissue
Group of similar cells that work together to carry out a particular function
Organ
Group of different tissues that work together to perform a particular function
Organ system
Group of organs working together to perform a particular function
Why can’t temperature be raised to speed up bodily reactions
- would speed up both useful and unwanted reactions
- cells would be damaged if temperature raised too high
Enzyme
Biological catalyst which increases the speed of a useful chemical reactions in the body without being changed or used up
How do enzymes get unique shape
- they are large proteins so made up of chains of amino acids
- chains folded into unique shapes
Active site
Enzyme’s uniquely shaped area where only substance involved in reaction binds
Induced fit enzyme model
Active site slightly changes shape as the substrate binds to get a tighter fit
Effect of temperature on enzymes
- higher temperature increases rate of reaction
- too high temperature breaks some bonds holding enzyme together, causing active site shape to change and substrate not fit
What does optimum temperature mean
Temperature which enzymes work best at
How does PH affect enzymes
Too high or low PH interferes with bonds holding enzyme together, changing shape of active site so substrate no longer fits
Optimum enzyme PH
- PH which enzymes work best at
- usually 7
Denatured enzyme
Enzyme which no longer works
Enzymes practical
- iodine drops in spotting tile
- Bunsen burner on heatproof mat with tripod and gauze over
- beaker of water on top heated to 35°C using thermometer
- syringe adds 1cm³ of amylase solution and 1cm³ of buffer solution with PH 5 to boiling tube
- place in test tube holders next to water for 5 minutes
- different syringe adds 5cm³ of starch solution to boiling tube
- mix boiling tube and start stop clock
- continuously sample how long it takes for amylase to break down starch
- use a pipette to drop fresh sample from boiling tube into iodine every 30 seconds until iodine is browny-orange
- repeat with different PHs
- calculate rate of reaction with 1000/time
What is amylase
A carbohydrase
What does amylase break down
Starch
What is starch broken down into
Glucose
Where is amylase made
- small intestine
- pancreas
- salivary glands
What does protease break down
Proteins
What is protein broken down into
Amino acids
Where is protease made
- small intestine
- pancreas
- stomach
What does lipase break down
Lipids
What are lipids broken down into
- fatty acids
- glycerol
Where is lipase made
- small intestine
- pancreas
Function of bile
- neutralises hydrochloric acid from stomach
- emulsifies fat
How does bile neutralise stomach acid
It is alkaline
Why must bile neutralise stomach acid
Enzymes in small intestine work best in alkaline conditions
Fat emulsification
Breaks fat down into tiny droplets with bigger surface area for lipase to act on, speeding up digestion
Where is bile produced
Liver
Where is bile stored
Gallbladder
Where is bile released into
Small intestine
Where are enzymes in digestive system produced
Specialised cells in gut lining
Salivary glands
Produce amylase in saliva
Oesophogus
- where food passes through to enter stomach
- uses peristalsis to contract and relax muscles and squeeze food down
Stomach
- pummels food with muscular walls
- produces protease enzyme - pepsin
- produces hydrochloric acid to kill bacteria and give right PH (2) for protease
Pancreas
Produces enzymes and releases them into small intestine
Small intestine
Digested food is absorbed out of digestive system into blood
Large intestine
Excess water is absorbed from food
Rectum
Where faeces is stored before leaving through anus
What mainly makes up faeces
Indigestible food
How to prepare food sample
- break up food in pestle and mortar
- add to beaker with distilled water
- stir with glass rod to dissolve
- filter using funnel and filter paper to get rid of solid bits
Types of sugars
- reducing
- non-reducing
How to test for reducing sugars
- add food sample to test tube
- add around 10 drops of Benedict’s solution using pipette
- place test tube in 75°C water bath for 5 minutes
Positive result for reducing sugars
Blue to green/yellow/brick-red
Negative result for reducing sugars
No colour change
How to test for starch
- add food sample to test tube
- add few drops of iodine and gently shake
Positive result for starch
Browny-orange to black blue
Negative result for starch
No change
How to test for proteins
- add food to test tube
- as biuret solution and gently shake
Positive result for protein
Blue to purple
Negative result for protein
No change
How to test for lipids
- add food to test tube
- add 3 drops of Sudan III solution and gently shake
Positive result for lipids
Mixture will separate into 2 layers with top bright red
Negative result for lipids
No separate layer
Where are lungs
In the thorax
Thorax
Top part of the body
What separates thorax from lower body
Diaphragm
What surrounds lungs
Rib cage and pleural membranes
Where does inhaled air go
Through the trachea, bronchi, bronchioles and into alveoli for gas exchange
What surrounds alveoli
Network of blood capillaries
How do alveolus carry out gas exchange
- oxygen diffuses from alveolus to blood
- carbon dioxide diffuses from blood to alveolus to be breathed out
How does gas exchange happen between body cells and blood
- oxygen diffuses from red blood cells to body cells
- carbon dioxide diffuses from body cells to blood and is carried back to lungs
What type of circulatory system do humans have
Double circulatory system
First circulatory system circuit
- right ventricle pumps deoxygenated blood to lungs to take in oxygen
- that blood returns to heart
Second circulatory system circuit
- left ventricle pumps oxygenated blood around the body
- deoxygenated blood returns to heart to be pumped to lungs again
What are walls of heart made of
Muscle tissue
Valves
Stop blood flowing backwards
Four chambers of the heart
- right atrium
- left atrium
- right ventricle
- left ventricle
Vena cava
Deoxygenated blood flows through from the body to the right atrium
How does blood go from atrial to ventricles
Atria contract
How does blood go from ventricles to atria
Ventricles contract
Pulmonary artery
Takes deoxygenated blood from heart to lungs
Pulmonary vein
Brings oxygenated blood from lungs to heart
Aorta
Takes oxygenated blood from heart to rest of body
Coronary artieries
Surround the heart and supply it with oxygenated blood
Pacemaker
- control resting heart rate
- group of cells in right atrium wall
- produce small electrical impulse which spreads to surrounding muscle cells, causing them to contract
Artificial pacemaker
- controls heartbeat if natural pacemaker doesn’t work properly
- little device implanted under skin with wire going into heart
- produces electrical rhythm to keep heart beating regularly
Types of blood vessel
- arteries
- capillaries
- veins
Arteries function
Carry blood away from heart
Arteries features
- strong elastic walls withstand high blood pressure
- thick layers of muscle
- elastic fibres allow them to stretch and spring back
- thick walls with small lumen
Capillaries function
Involved in exchange of materials at tissues
Capillaries features
- carry blood close to every cell for substance exchange
- permeable wall so substances can diffuse
- walls 1 cell thick to increase rate of diffusion by decreasing distance
Veins function
Carry blood back to the heart
Veins features
- thinner walls and bigger lumen as blood is lower pressure
- valves keep blood flowing in right direction
Four main things in blood
- red blood cells
- white blood cells
- platelets
- plasma
Red blood cells function
Carry oxygen from lungs to all cells in body
Red blood cells adaptations
- contain haemoglobin to carry oxygen molecules
- no nucleus allowing more space to carry oxygen
- biconcave shape (flat disc with side dips) increasing surface area to increase oxygen absorption
Haemoglobin
- in lungs, binds to oxygen to form oxyhaemoglobin
- in body cells, oxyhaemoglobin splits up and oxygen released into cells
White blood cells function
Defend against infection
How do white blood cells defend against infection
- change shape to kill unwanted microorganisms in phagocytosis
- produce antibodies to fight microorganisms
- produce antitoxins to neutralise toxins produced by microorganisms
- have nucleus
Platelets
Small fragments of cells with no nucleus which help blood clot at a wound to stop blood getting out and microorganisms
What does plasma contain
- red blood cells
- white blood cells
- platelets
- nutrients
- carbon dioxide
- urea
- hormones
- proteins
- antibodies
- antitoxins
Coronary heart disease
- coronary arteries get blocked by layers of fatty material building up
- arteries become narrow so blood flow is restricted
- lack of oxygen goes to heart muscle
- can cause heart attack
Methods of combating heart disease
- stents
- statins
Stents
Tubes inserted in arteries to keep them open so blood can pass through to heart muscles
Stents advantages
- effective for long time
- quick recovery time from surgery
Stents disadvantages
- risk of complications and infection from start
- risk of developing blood clot near stent (thrombosis)
Statins
- drugs that reduce bad LDL cholesterol in the blood stream
- slows down rate of fatty deposits forming
Statins advantages
- reduce risk of strokes, coronary heart disease, heart attacks
- increase good HDL cholesterol which can remove bad LDL cholesterol
- may prevent some other diseases
Statins disadvantages
- long term drug, must be taken regularly, may forget
- negative side effects, some serious (kidney failure)
- takes time for effect to work
Artificial heart
Mechanical device that pumps blood when a heart has failed until a donor heart is found
Artificial heart advantages
- less likely to be rejected by body’s immune system as there are no foreign cells
Artificial heart disadvantages
- surgery can lead to bleeding and infection
- electrical motor could fail
- blood doesn’t flow through as smoothly, can cause blood clots
- have to take drugs to thin blood which can cause problems with bleeding in an accident
Causes of valve damage
- heart attack
- infection
- old age
What can valve damage cause
- stiff valve tissue that doesn’t open properly
- leaky valve which lets blood flow both ways
- less effective blood circulation
Types of valve replacement
- biological
- mechanical
Advantages of valve replacements
- less drastic procedure
Disadvantages of valve replacements
- major surgery which can cause blood clots
Artificial blood
Blood substitute (like saline) used to replace lost blood, giving time for new blood cells to be produces
Advantages of artificial blood
Can keep patient alive when 2/3 of red blood cells lost
Disadvantages of artificial blood
Doesn’t contain red blood cells
Health
State of physical and mental wellbeing
What can cause better health
- balanced diet
- regular exercise
- getting enough sleep
What can cause worse health
- smoking
- stress
Disease
Condition which causes ill health
Types of disease
- communicable
- non-communicable
Communicable diseases
- spread from person to person
- spread from animal and animal/person
What can cause communicable diseases
Things like
- bacteria
- viruses
- parasites
- fungi
Examples of communicable diseases
- common cold
- meningitis
- malaria
Non-communicable diseases
- cannot spread between people or between animals
- not caused by a pathogen
Examples of non-communicable diseases
- asthma
- cancer
- coronary heart disease
What health problems can cause other health problems
- problems with immune system = more likely to catch communicable diseases
- HPV virus + more likely to get cervical cancer
When can mental health problems be triggered by physical health problems
- when they have an impact on a person’s ability to carry out everyday activities
- when they affect a persons life expectancy
What is a risk factor in disease
Things that are linked to an increased likelihood that a person with develop a certain disease in their lifetime
Risk factors that can cause disease directly
- smoking
- obesity
- drinking
- exposure to certain substances
- exposure to radiation
Costs of non communicable disease
- human cost to sufferers and loved ones
- financial cost of research and treating disease
- financial cost if a family member dies and income is reduced
What causes cancer
Uncontrolled cell growth and division resulting in formation of a tumour
Tumour
Mass of cells
Types of tumours
- benign
- malignant
Benign tumour
- grows until there is no more room and stays in place
- doesn’t invade other bodily tissues
- not cancerous
Malignant tumour
- grows and spreads into neighbouring healthy tissue
- cells can break off and travel to other parts of body though bloodstream, invading healthy tissue and forming secondary tumours
- cancerous
Cancer risk factors
- smoking can cause lung, mouth, bowel, stomach, cervical cancer
- obesity can cause bowel, liver, kidney cancer
- UV exposure can cause skin cancer
- viral infection like hepatitis B/C can cause liver cancer
- genetics - faulty genes can make you more susceptible to cancer
Plant organs
- stems
- roots
- leaves
- flower
Plant tissue
- epidermal
- palisade mesophyll
- spongy mesophyll
- xylem
- phloem
- meristem
Where is epidermal tissue
Covering entire plant
Epidermal tissue adaptations
- covered with a waxy cuticle which helps to reduce water loss by evaporation
- upper epidermis is transparent so light can pass through to palisade layer
Palisade mesophyll tissue
Where most photosynthesis takes place
Palisade mesophyll tissue adaptations
Lots of chloroplasts at top of leaf where they get the most light
Spongy mesophyll tissue
Contains big air spaces to allow gases to diffuse in and out of cells
Xylem and phloem tissue
Transport things like water, mineral ions and food around the plant
Xylem and phloem tissue adaptations
- form network of vascular bundles which deliver water and nutrients around the leaf and take away glucose from photosynthesis
- support leaf structure
Spongy mesophyll tissue adaptations
- contains air spaces to increase rate of diffusion of gases
What are phloem tubes made of
Elongated living cells with small pores in the end walls that allow cell sap to flow through
Translocation
Transportation of food substances (mainly dissolved sugars) made in leaves to rest of plant for immediate use or storage in both directions
What are xylem cells made up of
Dead cells joined end to end with no walls and a hole down the middle, strengthen by lignin
Lignin
Helps xylem cells withstand high water pressure
What do xylem tubes transport
- water
- mineral ions
Where do xylem tubes take water/mineral ions
From roots to stem and leaves
Transpiration stream
Movement of water from roots, through xylem and out of leaves
What causes transpiration
Evaporation and diffusion of water from plant’s surface
Where does most transpiration happen
Leaves
How is water in leaves lost by evaporation replaced
Drawn up from rest of plant through xylem vessels
What causes constant transpiration stream
- water lost from leaf by evaporation is replaced by being drawn up from rest of plant through xylem
- water is drawn up from roots to replace that
Factors affecting transpiration rate
- light intensity
- temperature
- air flow
- humidity
How does light intensity affect transpiration rate
- brighter light means greater rate
- stomata close as it gets darker as photosynthesis can’t happen so very little water can escape
How does temperature affect rate of transpiration
- warmer means faster rate
- water particles have more energy to evaporate and diffuse out stomata
How does air flow affect transpiration rate
- better air flow means faster rate
- when air flow is poor, (highly concentrated) water vapour surrounds leaf so diffusion can’t occur
- when air flow is good, water vapour is swept away so diffusion can occur
How does humidity affect transpiration rate
- drier air means faster rate
- in humid air, there is (highly concentrated) water vapour outside the leaf do diffusion can’t occur
What happens to guard cells when plant has lots of water
- fill with water and go plump and turgid
- opening stomata for gas exchange for photosynthesis
What happens to guard cells when plant is short of water
- lose water and become flaccid
- stomata close to stop water vapour escaping
What helps stomata open and close
- thin outer walls
- thick inner walls
How does light affect guard cells
Close and night when it’s dark as photosynthesis can’t happen
Why are there more stomata on underside of leaf
It’s shaded and cooler so less water is lost through stomata
