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Year 10 Mock revision Biology - Coggle Diagram
Year 10 Mock revision Biology
Cells, organisation and microscopy
Cells
are the basic building blocks of all organisms.
A
tissue
is a group of cells with a similar structure and function
Plant and animal cells are
eukaryotic
They have a cell membrane, cytoplasm and genetic material (DNA) enclosed in a nucleus
Animal sub cellular structures
Nucleus
-controls activities of the cell
Cytoplasm
- where most chemical reactions take place
Cell membrane
- controls the passage of substances into and out of the cell. It also contains receptor molecules.
Mitochondria
- where aerobic respiration takes place
Ribosomes
- where protein synthesis occurs.
Plant sub cellular structures
Chloroplasts
absorb light (using chlorophyll) to make food by photosynthesis
Permanent vacuole
- filled with cell sap
Cell wall
- made of cellulose and strengthens the cell
bacteria cells
are
prokaryotic
and much smaller in comparison
They have
cytoplasm
and a
cell membrane
surrounded by a
cell wall
The genetic material is not enclosed by a nucleus. It is a
single DNA loop
and there may be one or more small rings of
DNA plasmids
Specialised cells
Sperm cells
are specialised for reproduction
Long tail and streamlined head to help it swim
Lots of mitochondria to provide energy
Carries enzymes to digest the membrane of the egg
nerve cells
are specialised for rapid signalling
They are long to cover more distance
branched connections at their ends to connect to other nerve cells and form a network throughout the body.
muscle cells
are specialised for contraction
They are long so they have space to contract
They have lots of mitochondria to generate energy for contraction
root hair cells
are specialised for absorbing water and minerals
they have a big surface area to maximize opportunity for absorption of water and mineral ions
xylem and phloem cells
transport food and water around plant.
The cells are joined end to end to form tubes
xylem
are hollow at the centre
phloem
have few subcellular structures so that stuff can flow through them
Respiration
Respiration is
exothermic
because it transfers energy to the environment
The energy transferred supplies all the energy needed for living processes.
Respiration in cells can take place
aerobically
(using oxygen) or
anaerobically
(without oxygen) to transfer energy.
Aerobic respiration
glucose + oxygen → carbon dioxide + water + energy release
C6H12O6 + O2 = CO2 + H2O + energy
Anaerobic respiration
As the oxidation of glucose is incomplete in anaerobic respiration much less energy is transferred than in aerobic respiration.
The
heart
rate,
breathing
rate and breath
volume
increase during exercise to supply the muscles with more oxygenated blood. This enables increased cellular respiration so more
energy
is transferred to meet the demands of the muscle cells.
If
insufficient
oxygen is supplied,
anaerobic
respiration takes place in muscles. The
incomplete
oxidation of glucose causes a build-up of lactic acid and creates an oxygen
debt
. During long periods of vigorous activity muscles become fatigued and stop contracting efficiently.
Comparing aerobic and anaerobic respiration
Aerobic
requires oxygen
provides more energy compared to anaerobic respiration and is more efficient
occurs all the time in plants and animals
occurs inside mitochondrea
Produces water and carbon dioxide as waste products
Anaerobic
Only occurs if there is not enough oxygen
produces lactic acid
Only requires glucose
Creates oxygen debt
Does not transfer as much energy as aerobic respiration because the glucose isn't oxidised fully
creates muscle fatigue
Circulatory system
The
heart
is an organ that pumps blood around the body in a
double circulatory system
. (Heart to lungs to heart; heart to rest of body to heart)
Left
ventricle
right
ventricle
The left ventricle has a thicker wall with more muscle to generate a higher pressure to pump blood a longer distance to the rest of the body
left
atrium
right
atrium
Blood vessels
Arteries
carries oxygenated blood away from the heart
Thick walls as the blood is under pressure
elastic fibers and muscles even out the pressure in the artery
Small lumen, making the blood high pressure so it can be distributed around the body quickly
veins
carries low oxygenated blood away from organs towards the heart
Thin walls and large lumen to make a low pressure
Valves to stop the blood at low pressure flowing back
cappilaries
form a network of tiny vessels linking the arteries and veins
Narrow with thin walls so that oxygen and glucose can diffuse easily
One cell thick
Narrow lumen
The natural resting heart rate is controlled by a group of cells located in the right atrium that act as a pacemaker.
Red blood cells
contain haemoglobin which binds to oxygen to transport it from the lungs to the tissues.
In
coronary
heart disease layers of fatty material build up inside the coronary arteries, narrowing them, reducing the flow of blood and resulting in a lack of oxygen to the heart cells.
Stents
are used to keep the coronary arteries open.
Statins
are widely used to reduce blood cholesterol levels which slow down the rate of fatty material deposit.
In the case of
heart failure
a donor heart, or heart and lungs can be
transplanted
. Artificial hearts are occasionally used to keep patients alive whilst waiting for a heart transplant, or to allow the heart to rest as an aid to recovery
Plants
carbon dioxide + water →(light) glucose + oxygen
CO2 + H2O = (light) C6H12O6 + O2
Photosynthesis
is an endothermic reaction in which energy is transferred from the environment to the chloroplasts by light.
Rate of photosynthesis
Light
If there is more light, more photosynthesis can take place
Temperature
As temperature increases, the rate of photosynthesis increases
Photosynthesis is controlled by enzymes which denature around 40-50 degrees. Therefore, if the temperature gets too high, the enzymes denature and the rate of photosynthesis falls
Carbon dioxide concentration
Increasing the CO2 concentration increases the rate of photosynthesis
On a sunny day, CO2 concentration is usually the limiting factor for photosynthesis.
The CO2 concentrations around a plant rise at night because in the dark, plants respire but don't phtotosynthesize
RP6
-the effect of light on the rate of photosynthesis
Independent variable
= Distance from the lamp (affects light intensity)
Dependent variable
= Number of bubbles of oxygen
Control variables
=
Brightness of lamp
Colour of the light
Concentration of sodium hydrogen carbonate
Temperature
Length of pondweed
Type / species of pondweed
Light intensity
= 1/ Distance from light^2
Communicable diseases
Pathogens
are microorganisms that can cause infectious diseases
Viruses
Only reproduce inside host cells, no nucleus (viruses are not made of cells)
Bacteria
Cells with no nucleus, can produce toxins that damage tissues, treated with antibiotics
Protists
Cannot be classed as an animal, plant or fungus, cells have a nucleus
Malaria
Symptoms of recurrent episodes of
fever
, which can be fatal. Spread is controlled by preventing the
mosquito
vectors from breeding and by using mosquito nets to avoid being bitten.
Fungi
Treated with antifungals, cells have a nucleus
Pathogens
may infect plants or animals and can be spread by
direct contact, water or air.
Non-Communicable diseases
Traditionally drugs were extracted from
plants
and
microorganisms
.
The heart drug
digitalis
originates from
foxgloves
.
The painkiller
aspirin
originates from
willow
.
Penicillin
was discovered by Alexander Fleming from the
Penicillium mould.
Results of testing and trials are published only after scrutiny by peer review to help prevent false claims.
Different types of disease may interact:
Defects in the immune system that means an individual is more likely to suffer from infectious diseases
Viruses living in cells can be triggers for cancers
Immune reactions initially caused by a pathogen can trigger allergies such as skin rashes and asthma.
Severe physical ill health can lead to depression and other mental illness.
Monoclonal antibodie
s are specific to one binding site on one protein antigen. They can therefore target a specific chemical or type of cell within the body.
Mouse lymphocytes
are stimulated to produce a specific antibody
Lymphocytes
combined with a
tumour
cell to form
hybridoma
cells.
Hybridoma
cells both divide and make the antibody.
Single hybridoma cells
are cloned to produce many identical cells that all produce the same specific
antibody
.
A large amount of the
antibody
can be collected and purified.
Uses of
Monoclonal antibodies
Diagnosis: in pregnancy tests a monoclonal antibody binds to the hormone hCG produced by the embryo.
In laboratories: monoclonal antibodies are used to measure the levels of hormones and other chemicals in blood, or to detect pathogens.
In research: to locate or identify specific molecules in a cell or tissue by binding to them with a fluorescent dye.
To treat some diseases: for cancer the monoclonal antibody can be bound to a radioactive substance, a toxic drug or a chemical which stops cells growing and dividing.
Cell division
Cell cycle
Interphase
Before a cell can divide it needs to
grow and increase the number of sub-cellular structures
such as ribosomes and mitochondria. The
DNA replicates
to form two copies of each
chromosome
.
Mitosis
In mitosis one set of
chromosomes is pulled to each end
of the cell and the
nucleus divides.
Cytokinesis
Finally the
cytoplasm and cell membrane divides
to form two
identical
cells
Meristem tissue
can differentiate into any type of plant cell throughout the life of the cell
Produce clones of plants quickly and economically.
Rare species can be cloned to protect from extinction.
Crop plants with special features such as disease resistance can be cloned to produce large numbers of identical plants for farmers.
