Y10 MOCKS 1 Flashcards
AQA Biology GCSE 2024
What is a eukaryotic cell?
A cell which has a nucleus
What is a prokaryotic cell?
a cell which doesn’t have a nucleus
what is an example of a eukaryotic cell?
animal or plant cell
what is an example of a prokaryotic cell?
a bacterial cell
what is the function of a red blood cell?
to carry oxygen
what is the function of a guard cell?
allows gases to enter and leave the cell
what is the function of a root hair cell?
to absorb water and nutrients
what is the function of a sperm cell?
to fertilise an egg cell
what is the function of a nerve cell?
to carry electrical impulses
what is the function of a skin cell?
covers the body
what is the function of a palisade cell?
has lots of chloroplasts so it absorbs more light to increase the rate of photosynthesis
what is the function of an epithelial cell?
produces mucus
what is a cell?
the building block of living things
what is a tissue?
a group of cells with a similiar structure and function
what is an organ?
a collection of tissues working together to perform a function (e.g stomach)
what is an organ system?
a collection of organs working together to perform a function (e.g digestive system)
what is the function of the cell wall?
made of cellulose and strengthens the cell
what is the function of the mitochondria?
releases energy via respiration
what is the function of the vacuole?
filled with cell sap and keeps the cell rigid
what is the function of the chloroplasts?
contains chlorophyll to absorb light for photosynthesis
what is the function of the cytoplasm?
chemical reactions take place here
what is the function of the nucleus?
controls the cell and contains DNA
what is the function of the ribosomes?
a site of protein synthesis
what is the function of the cell membrane?
controls entry and exit of substances into the cell
what is the function of the epithelial tissue in the stomach?
protects the stomach by covering the inner and outer part of it
what is the function of muscle tissue in the stomach?
contracts for movement which churns the food
what is the function of glandular tissue in the stomach?
produces acid and enzymes
how has a sperm cell adapted?
has a tail to swim
has many mitochondria
head contains DNA and digestive enzymes
how has a nerve cell adapted?
long, thin fibres
how has a muscle cell adapted?
many mitochondria for energy
what are the 2 types of microscope?
electron and light
what are the advantages of a light microscope?
can study live specimens
cheap
portable
can see colour
what are the disadvantages of a light microscope?
lower resolution and magnification
what are the advantages of an electron microscope?
higher resolution and magnification
can see 3D images (cellular structures)
what are the disadvantages of an electron microscope?
expensive
don’t see colour
only work in a vacuum
bulky
affected by magnetic fields
what is the formula to calculate the magnification of a cell?
image size = magnification x actual size
what is mitosis needed for?
growth and repair
what is differentiation?
when cells become specialised to perform a function
what are stem cells?
unspecialised cells which can differentiate into different types of cells
where can stem cells be derived from in humans?
embryos or adult bone marrow
why are scientists experimenting with stem cells?
medical treatments and research
why are scientists experimenting with stem cells?
medical treatments and research
what is diffusion?
the movement of particles/dissolved substances from a high concentration to a low concentration down a concentration gradient until an equilibrium is reached. It is a passive process
what is osmosis?
the net movement of water from an area of high concentration to an an area of low water concentration across a semi-permeable membrane. It is a passive process
what is active transport?
the movement of particles/dissolved substances from an area of low concentration to an area of high concentration against the concentration gradient. It requires energy
what is the function of the mouth?
teeth and enzymes in saliva break down food
what is the function of the salivary gland?
produces saliva which contains enzymes
what is the function of the oesophagus?
transports food from mouth to stomach
what is the function of the stomach?
produces hydrochloric acid, food is broken down with enzymes
what is the function of the liver?
produces bile which neutralises the stomach acids so the enzymes don’t denature and it emulsifies fats
what is the function of the pancreas?
produces enzymes to break down food
what is the function of the gall bladder?
stores bile then releases it into the small intestine
what is the function of the small intestine?
it produces enzymes which break down food. the products are then absorbed into the blood
what is the function of the large intestine?
water is absorbed
what is the function of the rectum?
stores faeces
what is the function of the anus?
releases faeces
which order does food travel through the digestive system?
mouth -> oesophagus -> stomach -> small intestine -> large intestine -> rectum -> anus
what parts of the body are made of proteins?
enzymes, antibodies, hormones
what is a catalyst?
something that speeds up a chemical reaction without being used up
what is an enzyme?
a biological catalyst
what happens to enzymes at a high pH or temperature?
they denature, so the substrate no longer fits into the active site
what organs secrete amylase?
salivary gland
pancreas
small intestine
what organs are amylase secreted into?
mouth
small intestine
what does amylase do?
breaks down with starch to produce sugar
what organs secrete protease?
stomach
pancreas
small intestine
what organs is protease secreted into?
stomach
small intestine
what does protease do?
reacts with proteins to produce amino acids
what organs secrete lipase?
pancreas
small intestine
what organs is lipase secreted into?
small intestine
what does lipase do?
reacts with lipids to produce fatty acids and glycerol
where is hydrochloric acid secreted from?
the stomach
where is hydrochloric acid secreted into?
the stomach
where is bile made?
the liver
where is bile stored?
the gall bladder
where is bile secreted into?
the small intestine
what are the functions of hydrochloric acid?
to provide the best conditions for stomach enzymes
kills bacteria
what are the functions of bile?
neutralises stomach acid
enzymes in small intestine work best in alkaline conditions
emulsifies fats
what is the test for protein?
biurets reagent
blue -> purple
what is the test for starch?
iodine
orange/brown -> blue/black
what is the test for sugar?
benedict’s reagent + heat
blue -> red
how does temperature increase transpiration?
high temperature -> increased evaporation of water from leaf surface
how does humidity increase transpiration?
low humidity -> greater concentration gradient -> more water can evaporate
how does wind increase transpiration?
more wind -> greater air flow -> more water can evaporate from the leaf surface
how does light intensity increase transpiration?
higher light intensity -> stomata remain open to allow c02 to enter plant for photosynthesis -> more water can leave via the stomata
what are the adaptations of a root hair cell?
large SA
many mitochondria
Xylem’s structure
what are the adaptations of the xylem?
hollow tubes made of lignin
what are the adaptations of the phloem?
tubes of elongated cells
cell sap in the phloem moves from one cell to the next as there are pores in the end walls
what is the function of the meristem?
contains stem cells which can differentiate into other cell types
what is the function of the palisade mesophyll?
absorbs light for photosynthesis
what is the function of the spongy mesophyll?
gaps between cells allow gases to pass through easiliy
what is the function of the stomata/guard cells?
opens and closes by changing size to allow gases to enter and exit
controls transpiration
what is the function of the xylem?
transports water and ions
what is the function of the phloem?
transports sugars (translocation)
what are the types of pathogens?
bacteria
virus
protist
fungus
how do (bacterial) pathogens make us feel ill?
they produce toxins which damage our tissues and make us feel ill
how do viruses destroy cells?
viruses reproduce in cells which causes them to burst open/ causes cell damage
how does a vaccination make someone immune to a pathogen?
introduces small quantities of dead/inactive forms of a pathogen into the body
this stimulate the white blood cells to produce antibodies
this means that if the same pathogen re-enters the body, antibodies can be produced rapidly
how does the trachea/ bronchi defend against disease?
cilia (hairs) waft the mucus to the back of the throat where it is swallowed and goes to the stomach
how does the stomach defend against disease?
strong acids in the stomach (pH 2) kill most bacteria
how does the nose defend against disease?
nose hair traps pathogens
snot/mucus can trap pathogens
how does the skin defend against disease?
a layer of dead cells full of keratin acts as a physical barrier
produces antibacterial fluids
what is the first line of defence against disease?
your body’s natural barriers to infection
non-specific
what is the second line of defence?
phagocytosis (a type of white blood cell)
non-specific
6 billion per litre
describe phagoytosis?
phagocytes are attracted to pathogens when they have been ‘branded’ by antibodies
when a phagocyte comes into contact with a pathogen, it binds to it
the membrane of the phagocyte surrounds the pathogen, breaks it down with digestive enzymes and engulfs it into its vacuole
what is the third line of defence?
lymphocytes (a type of white blood cell)
specific
3 million per litre
how do lymphocytes defend against disease?
recognises one type of antigen and binds to it
lots of antibodies are produced which clump the pathogens together
this prevents them from entering cells and make them more vulnerable to phagocytosis
antibodies can also cause cell lysis
lymphocytes also produce antitoxins, which neutralise any toxins produced by the pathogen
memory lymphocytes are also made, which circulate the blood and provide long-term immunity
why does each lymphocyte have a specific antibody to attack a specific pathoogen?
each lymphocyte only produces one types of antibody. the binding site has a unique shape that will only match one type of antigen
what type of pathogen causes smallpox?
a virus
how was james phipps given immunity to smallpox?
he was infected with cowpox by edward jenner, which produced memory cells for it. the antibodies needed for smallpox and cowpox were similar, so his body could quickly find the antibodies needed for smallpox as well.
what happens if memory cells recognise an antigen?
they multiply to quickly destroy the pathogens. the antibody concentration stays high in case of another infection
how does ring vaccination work?
you only vaccinate people who have been in contact with the infected person
used if the virus mutates quickly or if there aren’t many vaccines
define monoclonal?
all one type
identical copies of one type of antibody
how is a hybridoma cell made?
b-lymphocytes from a mouse (specific)
+
tumour cells ( can divide)
I
membranes broken down with detergents or electricity
I
> hybridoma cell (MAKES specific antibodies + can divide)
monoclonal antibodies are then purified
name the main uses of monoclonal antibodies?
pregnancy/covid tests
locating/ identifying specific molecules by binding to them with fluorescent dye
diagnosing cancer
detecting pathogens/ measuring hormone levels
pros of monoclonal antibodies?
cancer: only combine with tumour cells, so healthy body cells wouldn’t be killed
they can also encourage your immune system to directly attack the cancerous cells
can be produced quickly
cons of monoclonal antibodies?
can produce immune responses from the foreign mous proteins
has lots of side effects like chills, fever, nausea and blood pressure changes
ethical issues
have previously resulted in a cytokine storm (organ failure)
what is the first clinical phase of drug trials?
small number of healthy male volunteers
testing for safety in humans
10-100
what is the second clinical phase of drug trials?
small number of infected patients
testing for effectivity, safety, dosage
100-400
what is the third clinical phase of drug trials?
large scale
3000+ volunteers
does it work for everyone?
testing for dosage and safety
uses placebo
what is the fourth clinical phase of drug trials?
rollout
takes over a decade
costs around half a billion pounds
why are drug trials peer-reviewed?
opposing companies are the most critical of their competitors
what is a preclinical drug trial?
tested on cells then genetically engineered mice
how does antibiotic resistance happen?
through mutation:
there are errors when the bacteria copies its DNA
some of these random mutations give the bacteria antibiotic resistance
the resistant bacteria survive and reproduce, increasing the resistant strain.
if antibiotic courses aren’t finished:
the most dangerous bacteria are left at the end, as the weakest bacteria are killed first
this means that any surviving resistant bacteria had loads of space to reproduce
what family does MRSA belong to?
staphylococcus
what do antibiotics do?
interfere with a pathogen’s metabolism
slow bacterial growth and reproduction long enough for the immune system to help
why is the heart referred to as a double circulatory system?
on one circuit of the body, the blood passes through the heart twice
how does the blood on the left side of the heart differ to the blood on the right side?
the blood on the left is oxygenated and higher pressure
what tissue makes up the heart?
muscle
what is the role of the coronary artery?
supplies oxygen and sugars to the heart
why is the left ventricle the biggest chamber?
it needs to have lots of strong muscle to pump blood all through the body, so the chamber is bigger and the muscle around it is thicker, so can contract more powerfully
what is the journey of the blood in the circulatory system?
lungs -> pulmonary vein -> left atrium ->ATRIO-VENTRICULAR VALVE-> left ventricle ->SEMI-LUNAR VALVE-> aorta -> rest of the body -> vena cava -> right atrium -> ATRIO-VENTRICULAR VALVE-> right ventricle ->SEMI-LUNAR VALVE -> pulmonary artery -> lungs