Biology - Topic 2 - Organisation
Biology - Topic 2 - Organisation
Lipids are broken down into glycerol and fatty acids.
Foods have to be broken down so that they can be small enough to be absorbed into the bloodstream.
A catalyst is a molecule/substance that increases the rate of reaction without being used up in the reaction. An enzyme is a biological catalyst made of proteins.
Enzymes - Protein molecule, biological catalyst.
Substrate - The reactant e.g. carbohydrates or protein.
Active Site - The part of the enzyme that the substrate fits in.
Amino Acid - Proteins are made of amino acids.
Enzymes in metabolism
Changing one molecule into another
Converting one simple sugar into another e.g. Glucose -> Fructose
Breaking down large molecules
Building large molecules e.g.
Proteins -> Amino Acids,
Lipids -> Glycerol and Fatty Acids
Glucose -> Starch, Glycogen or Cellulose
As temperature increases, the rate of reaction increases steadily until around 40 degrees Celsius when it drops suddenly as the enzyme is denatured, making the enzyme change shape and rendering the active site useless.
Veins - Carry deoxygenated blood to the heart.
large lumen, thinners walls, veins to prevent back flow
Arteries - Carry oxygenated blood away from the heart. Thick, elastic walls to withstand high pressure, smaller lumen
Capillaries - Smallest blood vessels. One cell wide, involved in the exchange of materials at the tissue.s
The heart consists of four main gas chambers: The left and right ventricle and the left and right atrium.
Resting heart rate
controlled by a group of
cells that act as a natural
Red blood cells - They carry oxygen and carbon dioxide and contain haemoglobin, a pigment which allows oxygen to bind to the red blood cells. It gives the cells their red colour.
adaptations - no nucleus to allow more room for harm ogle in, biconcave shape to increase surface area
White blood cells - Some can change shape to gobble up unwelcome microorganisms, in a process called phagocytosis.
Others produce antibodies to fight microorganisms, as well as antitoxins to neutralise any toxins produces by the microorganisms.
Unlike red blood cells, they do have a nucleus.
Plasma - It carries: Blood cells, platelets, nutrients (like glucose and amino acids), carbon dioxide, urea (part of urine), hormones, proteins, antibodies and antitoxins.
Platelets - The platelets are small, dead fragments of cells with no nucleus. They help to clot the blood at a wound to stop it from pouring out and to stop microorganisms from getting in. Lack of platelets can cause excessive bleeding and bruising.
Fat or cholesterol/Coronary heart disease
Stents - A wire mesh made from medical grade stainless steel or cobalt alloy. Inserted into the blood vessel and a small inflatable is inflated inside it to open the stent. The stent holds the fat deposits and vessel walls wider making it easier for blood to pass through.
Coronary heart disease is when the coronary arteries are blocked by fat deposits, which means the heart (cardiac) muscles don't have the required reactants for respiration.
Statins - Cholesterol is an essential lipid that your body produces and needs to function properly. However too much of a certain type of cholesterol (LDL cholesterol) can cause health problems. This "bad cholesterol" can cause a build up of fatty deposits in blood vessels and coronary heart disease. Statins are a drug that reduce the amount of "bad cholesterol" in the bloodstream.
Advantages: Reduce the risk of strokes, coronary heart disease, and heart attacks.
Can increase the amount of "good cholesterol" (HDL cholesterol) in the bloodstream.
May help to prevent other diseases.
Disadvantages: A long-term drug that must be taken regularly.
Can have negative side effects, some of which can be serious (kidney failure, liver damage, memory loss).
It takes time for the effect of statins to kick in.
Artificial heart - Artificial hearts are usually used as a temporary fix for heart failure, however they can be used as a long term solution if a donated heart can't be found. They are mechanical devices that pump blood around the body.
Faulty heart valves - Valves in the heart can be weakened by heart attacks, infections and old age. If valves stiffen or become leaky, which means that blood doesn't circulate as effectively as normal. Valves can be replaced with new ones, either biological (from another organism) or mechanical (man-made). This is much less drastic than a whole heart transplant but it is still a major surgical procedure.
Structure of lungs.
They're surrounded by the pleural membranes.
The air you breathe in goes through the trachea. This splits into two tubes called bronchi( two bronchus), one going to each lung.
These them split into bronchioles, these finally end at small bags called alveoli where gas exchange takes place.
Breathing rate= number of breaths/number of minutes
The lungs contain millions and millions of little air sacks, these are called the alveoli. This is where gaseous exchange happens.
CO2 diffuses out of the blood into the alveoli to be breathed out.
The blood passing next to the alveoli has just returned from the lungs. Meaning it has a lot of CO2 and little oxygen.
Oxygen diffuses out of the alveoli(high concentration) into the blood(low concentration).
When blood reaches body cells oxygen is released from the RBC and diffuses into the body cells.
At the same time, CO2 diffuses out of the body cells into the blood cells. It is then carried back to the lungs.
Interactions between disease that can lead to more ill health
defects to immune system - more likely to become infected
viruses that can damage living cells and lead to cancer (HPV —> cervical cancer)
immune reaction to pathogens can cause allergies
physical illness (acute or chronic) can lead to mental ill health - depression etc
Health - state of physical and mental well being
Disease - major causes of ill health
ill health may also be caused by - diet, stress, life situations,
Lifestyle and non communicable diseases
risk factors can be due to - lifestyle or - substances in a persons environment
has been proven for some risk factors
obesity - risk factor for type 2 diabetes
diet/smoking/exercise - risk factor for cardiovascular disease
smoking - lung cancer and lung disease
Transpiration and Translocation
Xylem tubes take water up
2)They carry water and mineral ions from the roots to the stern and leaves.
3)The movement of water from the roots, through the xylem and out of the leaves is called the transpiration stream.
1)Made of dead cells joined end to end with no walls between them and a hole down the middle, strengthened with lignin.
Transpiration is the loss of water from the plant.
2)This evaporation creates a slight shortage of water in the leaf and so more water is drawn up from the rest of the plant through the xylem vessels to replace it.
3)This in turn means more water is drawn up from the roots and so there's a constant transpiration stream of water through the plant.
1)Transpiration is caused by the evaporation and diffusion of water from a plants surface mostly at the leaves.
4)Transpiration is the loss of water from a plant. Transpiration is just a side effect of the way leaves are adapted photosynthesis. They have stomata in them so that gases can be exchanged easily. Because there's more water inside the plant than in the air outside, the water escapes from the leaves through the stomata by diffusion.
Phloem tubes transport food
2)They transport food substances made in the leaves to the rest of the plant.
3)The transport goes in both directions.
1)Made of columns of elongated living cells with small pores in the end walls to allow cell sap to flow through.
4)This process is called translocation.
1)Benign - Grows until there is no room and it stays in one place and doesn't invade other tissue. This is not cancerous.
2)Malignant - Grows and spreads to neighbouring healthy tissues, cells can break off and invade healthy tissues everywhere else and form secondary tumours, this is cancers.
2) Obesity - bowel, liver and kidney cancer.
3)UV exposure - skin cancer
1)Smoking - lung cancer
4)Viral Infection - Some virus can increase the chance of developing cancer.
5) Sometimes you can inherit faulty genes.
Plant cell organisation
Plant cells are organised into tissues and organs
Plants are made of organs such as stems, roots and leaves. These organs work together to make organ systems. These perform specific tasks such as transporting substances around the plant. Plant organs are made of tissue.
Examples of plant tissues:
: this covers the whole plant.
Palisade mesophyll tissue
: this is the part of the leaf where most photosynthesis happens
3)Spongy mesophyll tissue
this is also in the leaf, and contains big air spaces to allow gases to diffuse.
4) Xylem and Phloem
: these transport things like water, mineral ions and food around the plant.
5) Meristem tissue:
this is found at the growing tips of shoots and roots and is able to differentiate into lots of different types of plant cell, allowing the plant to grow.
The leaf is an organ made up of several types of tissue
Leaves contain epidermal, mesophyll, xylem and phloem tissue.
1) The epidermal tissue
is covered with a waxy cuticle, which helps to reduce water loss by evaporation.
2)The upper epidermis
is transparent so that light can pass through it to the palisade layer.
4)The xylem and phloem
from a network of vascular bundles, which deliver water and other nutrients to the entire leaf. It takes away glucose made from photosynthesis, they also help structure.
3) The palisade layer
has lots of chloroplasts( little structures were photosynthesis). This means that they're near the top of the leaf where they can get most light.
The tissues of leaves are also adapted for efficient gas exchange. The lower epidermis is full of little holes called stomata, which let CO2 diffuse directly into the leaf.
The opening and closing of stomata is controlled by guard cells in response to environmental conditions. The air spaces in the spongy mesophyll tissue increase the rate of diffusion of gases.
Transpiration and Stomata
Transpiration rate is affected -
2)The higher the temperature the greater the transpiration rate.(Evaporation)
3)The better the airflow the more water vapour is swept away.
1) The brighter the light the greater the transpiration rate.(Photosynthesis)
4)The drier the air around a leaf the faster the transpiration, as humid air already has a lot of water so diffusion isn't as effective.
Guard cells -
4)Thin outer walls and thick inner walls.
this cases uneven flexibility - therefore cells curve - opening the pore
5)Sensitive to light and close at night to save water.
3)When the plant cell loses water the guard cells become flaccid and the close stopping the loss of water vapour.
6)Find more stomata on the underside of the leaves, shaded and cooler so less water is lost.
2)When the plant has lots of water the fill up and open so gases can be exchanged for photosynthesis.
7)Guard cells are therefore adapted for gas exchange and controlling water loss within a leaf.
1)Opens and closes the stomata.
Digestive System Organs.
Salivary Glands - These produce
Gullet - (Oesophagus) Food travels down here.
Liver - Where
is produced. Bile
neutralises stomach acid
the food with its muscular walls. It produces the
. It produces
give the right pH
enzyme to work.
Gallbladder - Where
before it's released into the
Pancreas - Produces
enzymes. It releases these into the
Small Intestine - Produces
emzymes to comlete digestion. Also where digested food is
out of the digestive system into the blood.
Large Intestine - where
from the food.
Rectum - Where the
is stored before exiting through the
Enzymes used in the digestive system are produced by specialised cells in
and in the
2 Different enzymes catalyse breakdown of different food molecules.
enzymes and their substrates
carbohydrases break down carbohydrates into simple sugar molecules
proteases break down proteins in to amino acids
lipases break down lipids into glycerol and fatty acids