Topic 2 - Organisation Flashcards
Define the role of a cell membrane
controls what enters and leaves the cell
Define the role of mitochondria
where respiration happens (which releases energy)
Define the role of cytoplasm
where chemical reactions occur
Define the role of ribosomes
create proteins
Define the roles of a nucleus
contains DNA, controls the cell
What is the order (from smallest to largest) of organisation?
cells - tissues - organs - organ system - organism
Define a cell
basic unit of an organism
Define a tissue
a group of SIMILAR cells working together to carry out a specific function
Define an organ
a group of different tissues working together to carry out functions
Define an organ system
a group of organs working together to carry out a specific function
Define an organism
a group of organ systems working together
What type of cell has extra mitochondria and why?
muscle cells have extra mitochondria because it moves so it needs lots of energy (and mitochondria releases energy through respiration)
What does the muscle tissue do?
contracts to move the cell
What does the epitherial tissue do?
lines the tubes and the skin
What does the skeletal tissue do?
supports and protects the body
What does the nerve tissue do?
carries electrical signals around the body
What does the glandular tissue do?
produces hormones and enzymes
Define an enzyme
enzymes are biological catalysts which speed up chemical reactions in the body
Explain what happens when enzymes catalyse reactions
Enzymes have an active site with a unique shape that fits onto the substance in the reaction. The substrate binds to the active site (fitting perfectly) and the enzyme breaks down the substrate into products.
Name 4 factors that affect enzymes:
- temperature
- concentration of enzyme
- concentration of substrate
- pH
Define a denatured enzyme
active site has changed shape permanently (meaning it doesn’t work anymore) due to temperature or pH
Explain how temperature affects enzyme activity
the higher the temp, enzyme activity increases till a certain point. the enzyme will reach an optimum temperature (usually around 40 degrees) then decrease rapidly because the enzymes start to denature(so they can’t bind to an active site)
Function of mouth and salivary glands
chews food and adds saliva
Function of oesophagus
takes food to stomach
Function of stomach
mixes food and adds acid/protease
Function of liver
adds bile
Function of gall bladder
stores bile
Function of pancreas
make enzymes
Function of small intestine
enzymes, food absorbed into blood
Function of large intestine
absorbs water
Function of rectum
stores faeces
Function of anus
faeces leaves
State which 4 digestive organs produce enzymes
salivary glands, stomach, pancreas, small intestine
Amylase:
Where is it made?
What does it breakdown?
What are the product(s)?
- made in salivary glands, pancreas, small intestine
- breaks down starch and makes glucose
Protease:
Where is it made?
What does it breakdown?
What are the product(s)?
- made in pancreas, stomach, small intestine
- breaks down proteins and makes amino acids
Lipase:
Where is it made?
What does it breakdown?
What are the product(s)?
- made in pancreas, small intestine
- breaks down lipids (fats) and makes fatty acids and glycerol
What are the two roles of bile?
neutralises stomach acid and breaks down/digests fat
Give the reagent and colour changes for the starch test
iodine SOLUTION - orangy brown to a bluey black
Give the reagent and colour changes for the sugar test
benedicts (+heat) - blue to a brick red
Give the reagent and colour changes for the protein test
biuret - blue to purple
Give the reagent and colour changes for the fat test
ethanol + water - clear to cloudy
Give three adaptations of the alveoli
- good blood supply maintains steep concentration gradient
- spherical shape means a large surface area
- lined with moisture so oxygen can dissolve into blood
Why is the left ventricle wall thicker?
It has to pump the blood all the way around the body whereas the right ventricle only has to pump blood to the lungs
Where are the cells that act as a natural pacemaker for the heart located?
right atrium
Give 4 features of arteries
- narrow lumen
- thick muscular walls
- carries blood under high pressure
- usually carries oxygenated blood (except pulmonary)
Give 4 features of veins
- large lumen
- thin muscular walls
- carries blood under low pressure
- usually carries deoxygenated blood (except pulmonary)
Give 4 features of capillaries
- so narrow blood cells can barely squeeze through
- walls are one cell thick
- blood loses pressure as it passes through
- where substances are exchanged between blood and body
Name the 4 components of blood and their role
white blood cell - fights infection
red blood cell - carries oxygen
plasma - carries carbon dioxide, urea, hormones etc.
platelets - cell fragments that help blood clot and prevent bleeding
Name 4 substances the blood carries
oxygen, hormones, nutrients, carbon dioxide
What are statins and give some pros and cons?
Drugs that lower cholesterol levels. Easy and no surgery but side effects (e.g headaches)
What are stents and give some pros and cons?
Metal tubes that hold arteries open. Long lasting and effective but surgery risks
Define health
state of physical and mental wellbeing
Define a communicable disease
diseases that can be spread from person to person e.g flu
Define a non-communicable disease
diseases that can’t be spread but are usually caused by unhealthy behaviours e.g cancer
Name 3 risk factors a disease they are associated with
smoking - lung cancer
obesity - type 2 diabetes
diet, smoking, exercise - cardiovascular disease
What is cancer?
uncontrolled cell growth
What is a tumour?
a mass of cells (usually cancerous)
What is mutation?
when DNA is damaged
Define benign and maliginant tumours
benign tumours grow within a membrane and don’t spread and malignant tumours can spread to other body parts via the blood
When can benign tumours become a problem?
when they become too large they can put pressure on organs and damage them
What are secondary cancers?
cancers that are formed as a result of malignant tumours
Define waxy cuticle layer
Layer of wax on top of leaf which stops water loss
Define the upper epidermis
thin layer of transparent cells on top of leaf
Define the palisade layer
tall, tightly packed cells with lots of chloroplasts for photosynthesis
Define the spongy mesophyll layer
less tightly packed cells with lots of air spaces
Define the guard cells
cells that fill with water to open holes in leaf for more photosynthesis
Define the stomata
the name of the holes in the leaf that allow gases in and out of the leaf
Define the xylem
tubes that transport water and minerals up the stem from roots to leaf
Define the phloem
tubes that transport sugars both up and down the stem
Define transpiration
the loss of water from a plant due to evaporation
What is meristem tissue and where is it found?
actively dividing cells which promote plant growth and they are found in root tips, shoots, buds and anywhere where new growth occurs
What instrument is used to measure rate of transpiration?
potometer
Describe the xylem
- transports water and mineral ions
- movement is upwards
- formed from toughened dead cells
- strengthened by lignin
- provides support
Describe the phloem
- transports sugar (translocation)
- cell sap moves through the sieve plates
- movement is up and down
- formed from living cells
How do guard cells open the stomata?
- ions are pumped into the guard cell
- so there’s a lower water concentration in the cell
- so water moves into the cell by osmosis
- the guard cells swell and curve - they’re open
What are nitrates used for in plants?
- used to make proteins
- nitrate + glucose –> amino acids
What are the symptoms of a plant being deficient in nitrates?
- stunted growth
- yellow leaves
What is magnesium used for in plants?
used to make chlorophyll
What are the symptoms of a plant being deficient in magnesium?
- yellow leaves
