ORGANISATION Flashcards
what is differentiation?
the process in which a cell becomes speciallised for a function
when does differentiation occur?
during the development if multicellular organism
what do speciallised cells form?
tissues which then form organs which then form organ systems
what is a tissue?
a group of similar cells that work together to carry out a specific function
give examples of tissues types in mammals (3)
muscular - contracts to move
glandular - makes/secrets chemicals (enzymes/hormones)
epithelial - covers part of the body
what is an organ system?
a group of organs working together to perform a function
organ systems work together to form..
organisms
what are enzymes?
catalysts produced by living things
what is a catalyst?
a substance that increases the speed of a reaction without being used up/changed
what is an enzyme?
proteins that act as biological catalysts
what does every enzyme have?
an active site with a unique shape that fits onto the substance involved
what is an induced fit of enzyme action?
when the active sit changes shape as the substances binds to get a tighter fit
enzymes need the right….
temperature
pH
why do enzymes need the right temperature?
changing the temp vhanges the rate of an enzyme-catalysed reaction.
temp increases it
too hot -> bonds of enzymes break -> changes shape of active site - substrate wont fit
all enzymes have an optimum temp they work best at
why do enzymes need the right pH?
too high/low -> bond is effected -> shape of active site changes -> enzyme denatures
optimum pH is usually 7
pepsin works best at pH 1-2
enzyme PRACTICAL
- put a drop of iodine solution in every well of a spotting tile
- place a bunsen burner on a heat proof mat
- put a tripod and gauze over the bunsen burnder
- put a beaker of water on the tripod
- heat the water til its at 35C using a thermometer to track it
- use a syringe to add 1cm3 of amylase and 1cm3 of buffer solution with a pH of 5 to a boiling tube
- using test tube holders, put them into the beaker of water
- wait for 5 mins
- add 5cm3 of starch solution to the boiling tube
- mix everything in the boiling tube and start a stopwatch
- using a pipette, take a sample of the boiling tube every 30s and add a drop to a well
- when the iodine stays browny-orange, starch is no longer present and stop the stopwatch
- repeat experiment with different pH to see how pH affects time taken for starch to break down
rate of reaction =
1000/time
why are big molecules (starch, fat, protein) broken down?
theyre too big to pass through walls of the digestive system so digestive enzymes break them down to sugars, amino acid, glycerol and fatty acids which can be absorbed into the bloodstream
carbohydrase converts….
carbohydrates to simple sugars e.g amylase - made in salivary glands, pancreas, small intestine
protease converts….
proteins to amino acids
protease is made in stomach (pepsin), pancreas, small intestine
lipases converts…
lipids into glycerol and fatty acids
lipase made in pancreas and small intestine
what does bile do?
neutralises stomach acid - hydrochloric acid in the stomach makes it too acidic for enzymes to work properly. bile is alkaline which will neutralise the acid
emulsifies fat (breaks down fat) - bigger SA for lipase to work on, speeding up digestion
where is bile produced?
liver
where is bile stored?
gall bladder
what is the breakdown of food catalysed by?
enzymes
where are digestive enzymes produced in?
by cells in the glands and gut lining
what do salivary glands produce?
amylase enzyme in the saliva
what is the gullet?
oesophagus
what is produced in the liver?
bile
what does the gall bladder do?
stores bile before its released into the small intestine
where is excess water is absorbed?
large intestine
what is stored in the rectum?
faeces
what does the small intestine do?
produces protease, amylase and lipase enzymes
digested food is absorbed out, into the blood
what does the pancreas do?
produces protease, amylase and lipase enzymes
releases them into small intestine
what does the stomach do?
pummels food with its muscular walls
produces pepsin and hydrochloric acid (to kill bacteria and give right pH (2) for pepsin to work
food test PRACTICAL - preparing food sample
- get a peice of food and break it up using a pestle and mortar
- transfer the ground up food into a beaker
- add some distilled water to the beaker
- mix it to dissolve it
- filter the solution using a funnel lined with filter paper to get rid of solid bits
testing for sugar PRACTICAL (bendict)
- prepare a food sample
- put 5cm3 of it into a test tube
- set a water bath to 75C
- add benedict solution to the test tube using a pipette
- put the test tube in the bater bath and leave for 5 mins
- if it contains sugar: blue -> green, yellow or brick-red (depending on the amount of sugar in it)
testing for starch PRACTICAL (iodine)
- transfer 5cm3 of the food sample to a test tube
- add some iodine using a piette
- gently shake the test tube to mix the contents
- if starch is present: brown/orange -> blue/black
testing for proteins PRACTICAL (biuret)
- transfer 2cm3 of food sample into a test tube
- add 2cm3 of biuret solution to the sample and gently shake
- if contains protein: blue -> purple
testing for lipids PRACTICAL (sudan III)
- transfer 5cm3 of the unfiltered food sample to a test tube
- use a piette to add 3 drops of sudan III solution
- gently shake the test tube
- if lipids present: mixture will be separated into 2 layers (top layer bright red)
what is the bronchi split into?
bronchioles
where does gaseous exchange take place?
in the lungs where millions of alveoli exist, surrounded by capillaries
what is the pathway of oxygen (gaseous exchange)?
air enters through the nose/mouth -> throat (pharynx) and passes through the voice box (larynx) -> trachea -> left/right bronchus -> bronchioles -> alveoli
what is the pathway of blood (circulatory system)?
deoxygenated blood:
superior vena cava -> right atrium -> right ventricle -> pulmonary valve -> pulmonary arteries -> lungs (gaseous exchange)
oxygenated blood:
pulmonary vein -> left atrium -> left ventricle -> aorta -> body
what are the walls of the heart made of?
muscle tissue
what feature of the heart prevents backflow of blood?
valves
where is the pacemaker?
atrium or ventricle
what does the pacemaker cells do?
send electrical impulses which spreads to other muscle cells which causes them to contract
what are the different types of blood vessels?
arteries
veins
capillaries
what are features of arteries?
carry blood under high pressure
walls are strong, thick and elastic
what are features of capillaries (arteries are branched into) ?
thin wall (one cell thick) - faster diffusion -> less distance
permable wall - allow diffusion
supply food and oxygen
carry blood close to every cell to exchange substances
what are the features of veins (capillaries joined up)?
big lumen
keep blood from backflowing
blood is at low pressure so thick walls aren’t needed
rate of blood flow=
vol of blood/time
what is blood?
a tissue
what is the function of red blood cells?
to carry oxygen from the lungs to the body
what are the features of red blood cells?
biconcave disc shaped > large SA ->absorbtion of oxygen
no nucleus -> more space to carry oxygen
red pigment (haemoglobin)
what happens to haemoglobin in the lungs?
binds with oxygen to form oxyhaemoglobin
what happens to oxyhaemoglobin in tissues?
splits into haemoglobin and oxygen to release oxygen to cells
what is the function of white blood cells?
fight off infection
what is phagocytosis?
when white blood cells change shape to engulf unwelcomed microorganisms
how do white blood cells fight off infection?
produce antibodies and antitoxins (neutralises toxins produced by microorganisms)
what do platelets do?
help blood clots - stop blood pouring out and stops microoganisms getting in
what are platelets?
small fragments of cells with no nucleus
what happens if you don’t have enough platelets?
excessive bleeding
brusing
what is plasma?
the liquid that carries everything in blood (pale/straw coloured)
what does plasma carry?
red and white blood cells
platelets
nutrients (glucose, amino acids)
CO2 from organs to lungs
urea from liver to kidneys
hormones
antibodies and antitoxins
what is coronary heart disease?
when coronary arteries that supply blood to muscles of heart, get blocked by layers of fat -> arteries become narrow so blood flow is restricted -> lack of oxygen to heart muscles -> heart attack
what are stents?
tubes inserted inside arteries
what do stents do?
keep arteries open, making sure blood can pass -> keeps heart beating
what are the advantages of stents?
effective for a long period
fast recovery time
what are the disadvantages of stents?
complications during the surgery
risk of infection
thrombosis - blood clot near stent
what is cholestrol?
essential liquid that your body needs and produces
what happens if you have too much LDL cholestrol?
causes fatty deposits inside arteries -> coronary heart disease
what are statins?
drugs that reduce amount of LDL cholestrol present -> slows down rate of fatty deposits forming
what are the advantages of statins?
reduced risk of strokes, coronary heart disease and heart attacks
increase HDL cholestrol -> removes LDL
what are the disadvantages of statins?
long term drug that needs to be taken regularly
negative side effects e.g headaches, kidney failure
effect isn’t instant
what is an artifical heart?
mechanical devices that pump blood for someone that heart has failed - temporary -> keeps person alive until donor is found
what are the advantages of an artificial heart?
can be permanent
less likely to be rejected -> made of metals and plastic -> not seen as foreign -> body won’t attack
what are the disadvantages of an artificial heart?
bleeding
infection
not as healthy of natural heart - parts of it wear out or electric motor could fail
blood doesn’t flow as smooth -> lead to blood clots and strokes
what damages heart valves?
heart attacks
infection
old age
what is the dangers of a damaged heart valve?
valve tissue stiffens -> doesn’t open properly/becomes leaky -> blood flows in both directions -> blood doesnt’t circulate as effectively
how are damaged valves replaced?
replacememt valves are taken from humans or other mammals (biological valves) or man-made (mechanical valves)
what is artificial blood?
blood substitue e.g salt solution
what does artifical blood do?
when in an accident, heart can still pump the remaining red blood cells around body for oxygen as long as volume of blood can be topped up. this replaces the lost vol of blood -> gives time for body to produce new blood cells
what is health?
the state of physical and mental wellbeing
what is a communicable disease?
disease that spreads between people/animals e.g measles and malaria
what are communicable diseases caused by?
bacteria, fungi, parasites, viruses
what is a non-communicable disease?
disease that cannot spread between people/animals e.g asthma, cancer, coronary heart disease
what is a pathogen?
microorganism that causes disease
what affects health?
amount of stress
diet (provides body with everything needed)
life situation - access to health care etc
what are costs of non-communicable disease (human and financial)?
human - 10s of millions die annually, shortens life span
financial - NHS researching and treating, health services, families may have to move homes OR change/quit job, less people to work
how does smoking cause lung damage/cancer?
damages walls of arteries and cells in the lining of the lungs
what are the direct risk factors of disease?
excessive alcohol: -> liver disease - damage liver cells (toxic chemicals), damage intestines
->affects brain functioning - damages nerve cells, brain loses volume
smoking (when preg): -> health problems for baby - reduces amount of oxygen baby recieve
what causes cancer?
carcinogens + exposure to radiation + uncontrolled cell growth and division
what is a benign tumour?
when a tumour grows until no space left, it stays in one place (within a membrane), not usually dangerous or cancerous
what is a malignant tumour?
when a tumour grows and spreads to healthy tissues -> cells break off and go to other body parts via bloodstream to form a secondary tumour
dangerous and fatal
what are the risk factors of cancer?
smoking -> lung, mouth, bowel, stomach, cervical cancer
obesity -> bowel, liver, kidney cancer
UV exposure -> skin cancer
viral infections -> hepatitis B and C increases risk of liver cancer
what are plant organs?
stem, roots, leaves
what are plant organs made of?
tissues
what are the plant tissues and functions?
epidermal - covers the plant
palisade mesophyll (in leaf) -> photosynthesis
spongy mesophyll - big air spaces -> allow gases to diffuse
xylem/phloem -> transport water and mineral ions
meristem tissue (growing tips of shoots and roots) -> differentiate -> plant can grow
what is the structure of the tissues and functions?
epidermal - covered in waxy cuticle -> reduce water loss
upper epidermis - transparent -> light can pass to reach palisade
palisade - chloroplasts -> photosynthesis
xylem/phloem - network of vascular bundles -> deliver water and mineral ions, support structure
lower epidermis - lots of stomata -> co2 diffuse directly into leaf
stomata -> opening/closing controlled by guard cells
what is the function of phloem?
transport food in both directions - translocation
how is phloem adapted for its function?
columns of elongated cells with small pores at the end -> allows cell sap to flow through
what is the function of xylem?
carry water and mineral ions from roots to stems and leaves
how is xylem adapted for its function?
made of dead cells joined end to end - strengthened by lignin
what is the transpiration stream?
the movement of water from the roots and out of leaves by xylem
what causes transpiration caused by?
evaporation and diffusion - usually in leaves
what affects transpiration rate?
high light intensity -> stomata closes when its dark so no water can escape (photosynthesis cant happen in the dark)
high temp -> water particles have more energy to diffuse in/out of stomata
good air flow -> water vapour is swept away to maintain low conc of water in air
humidity (dry)-> if air is humid theres already lots of water in it
when does diffusion happen the fastest?
when theres a high conc in one place and a low in another
how do you estimate transpiration rate?
using a potometer
how do you use a potometer?
1) set it up and record the starting position of air bubble
2) start a stopwatch
3) record the distance moved by bubble per time
4) keep conditions constant
what do guard cells do?
open and close stomata
how do guard cells work?
lots of water -> guard cell fills with it and go plump and turgid -> stomata opens and gases can be exchanged for photosynthesis
little water ->guard cell loses water and becomes flaccid -> stomata close (stops water from escaping)
what are the adaptions of guard cells?
thin outer walls
thick inner walls
sensitive to light so close at night
where is the stomata mainly found?
undersides of leaves - shaded and cooler -> less water is lost
what is plasma?
liquid base for blood
