Biology

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  • Created by: Ash2mili
  • Created on: 15-01-18 14:48
properties of water that make it a good transport medium:
Water is a very good transport medium. • Water is liquid at room temperature. • The hydrogen's in the water push away from each other making the molecule V shaped. • many water molecules can bond together forming hydrogen bonds, as the negatively cha
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Closed circulatory systems:
• Blood leaves heart under pressure # arteries # arterioles # capillaries • Capillaries come in large numbers. They exchange substances between the blood and cells. • After passing through capillaries # blood goes back to the heart via venules # vein
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How does blood move through the vessels?
to accommodate the blood. During relaxation of the heart (diastole) the elasticity of the walls causes them to recoil • behind the blood pushing the blood forward. How the valves in veins work: Blood passes through the vein • skeletal muscles contra
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The heart and blood vessels
The heart consists of: • Aorta (to body) • Pulmonary artery (to lungs) • Pulmonary veins (from lungs) • Left and right atrium • Left and right ventricle • Atrioventricular valves (separates the ventricles and atrium) • Semi-lunar valve (separates the
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How the heart works continued
Phase 3: Diastole Atria and ventricles relax during diastole. • Elastic recoil lowers pressure in the atria and ventricles. • Blood under higher pressure in the arteries is drawn back towards the ventricles, closing • the semi-lunar valves. The coron
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Blood clot
When blood vessel walls are damaged a blood clot is likely to form. Platelets come into contact with vessel wall and change from flat discs to spheres with • long thin projections. this change causes them to stick to the exposed collagen in the wall
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What is atherosclerosis?
Atherosclerosis can lead to coronary heart disease and strokes. It does this by blocking an artery with fatty deposits . Stages of atherosclerosis: • Endothelium becomes damaged (e.g. due to high blood pressure, or cigarette smoke) • Damage causes in
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Identifying risk factors for CVD continued
Rick factors that increase the chance of getting CVD: High blood pressure • Obesity • Blood cholesterol and other dietary factors • Smoking • Genetic inheritance • The risk of CVD is higher for men than women in the UK. The risk of getting CVD also i
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Sugars
Mono-saccharides are single sugar units. They can be joined in condensation reactions to form disaccharides which are made of two mono-saccharides. They can also be joined together to form polysaccharides which contain three or more sugar units. When
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Starch, glycogen and cellulose
Starch is made up of a mixture of two molecules, found in many foods such as fruit and vegetables. : Amylose straight chain between 200 and 500 glucose molecules in length • 1,4 glycosidic links between adjacent glucose molecules • chain is coiled in
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Lipids
Lipids enhance the flavour and palatability of food. They are insoluble in water but soluble in organic solvents such as ethanol. The most common lipids we eat are triglycerides: • used as energy stores in plants and animals • they are made up of thr
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The energy balance
A constant supply of energy is needed to maintain your essential body processes (e.g. pumping (BMR) basal metabolic rate the heart). The amount of energy needed for this is called the BMR is higher in: Males • Heavier people • Younger people • More
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Cholesterol
Cholesterol is not soluble in water. To be transported in the bloodstream it is combined with proteins to form soluble lipoproteins. There are two main types of lipoprotein these are: Low density lipoprotein (LDL's): • main cholesterol carrier in the
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Smoking and inactivity
Smoke The haemoglobin in the red blood cells carries carbon monoxide instead of oxygen, • reducing the amount of oxygen that gets to the cells Nicotine in smoke stimulates the production of the hormone adrenaline. This hormone • causes an increase in
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Cystic fibrosis (CF)
CF problems: • CF is caused by a faulty transport protein in the surface membranes of epithelial cells • CF creates a sticky mucus layer that lines the tubes and ducts in the gas exchange, digestive and reproductive systems. • The sticky mucus increa
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Gas exchange
Features of a good gas exchange surface: large surface area for the alveoli • numerous capillaries around the alveoli • thin walls of the alvioli and capillaries meaning a short distance between the alveolar air • and the blood in the capillaries The
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Fluid mosaic model
The cell surface membrane consists of: Phospholipid bilayer (all the molecules are arranged so that the hydrophobic tails are inside • the bilayer) proteins • cholesterol • glycoproteins (protein molecules with polysaccharides attached) • glycolipids
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How do substances pass through cell membranes?
Molecules and ions move across membranes by: • diffusion • osmosis • active transport • exocytosis • endocytosis Diffusion: (or passive transport) Diffusion is the net movement of molecules from a region where they are at a higher concentration to a
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Transport across the cell membrane
Diffusion : High to low concentration until equilibrium reached • hydrophobic (lipid - soluble) or small uncharged molecules • through phospholipid bilayer • passive, no energy required • Facilitated diffusion: high to low concentration until equilib
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Regulating water in the mucus in affected lungs
With excess water: Na+ is actively pumped across the basal membrane • Na+ diffuses through sodium channels in the apical membrane • Cl- diffuses down electrical gradient • water is drawn out of cells by osmosis due to the high salt concentration in t
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Effect of CF on digestive system
• In a person with CF the pancreatic duct becomes blocked by sticky mucus, impairing the release of digestive enzymes. • The lower concentration of enzymes within the small intestine reduces the rate of digestion. • Because of this the food is not fu
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Enzymes
Enzymes are globular proteins that act ad biological catalysts (They speed up chemical reactions). There is a depression on the surface of the enzyme molecule called the active site. Lock and Key theory: a molecule with a complimentary shape can fit
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The structure of DNA
Gene and genome: a gene is a sequence of bases on a DNA molecule coding for a sequence of amino acids in a polypeptide chain. Together all genes in a individual are known as the genome. DNA is a chain of nucleotides: DNA is one type of nucleic acid,
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DNA
There are four bases: • adenine (A) • cytosine (C) • guanine (G) • thymine (T) In DNA there are two long strands of nucleotides twisted around to form a double helix. The sugars and phosphates are on the outside, and the bases point inwards and are h
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Protein synthesis
Transcription: (in the nucleus) DNA double helix unwinds and hydrogen bonds break • the template strand is used in the production of a messenger RNA molecule • every triplet code on DNA gives rise to a complimentary codon on messenger RNA • the compl
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DNA replication
When a cell divides an exact copy of the DNA must be produced so that each of the daughter cells receives a copy This process of copying the DNA is called replication. There are three possible ways DNA could replicate: • fragmentary replication - all
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What goes wrong with DNA?
Mistakes in replication: Sometimes DNA replication does not work properly. As the new strand of DNA is being built and incorrect base may slip into place. Sickle cell anemia: mutation in the gene that codes for one of the polypeptide chains in haemog
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Other cards in this set

Card 2

Front

• Blood leaves heart under pressure # arteries # arterioles # capillaries • Capillaries come in large numbers. They exchange substances between the blood and cells. • After passing through capillaries # blood goes back to the heart via venules # vein

Back

Closed circulatory systems:

Card 3

Front

to accommodate the blood. During relaxation of the heart (diastole) the elasticity of the walls causes them to recoil • behind the blood pushing the blood forward. How the valves in veins work: Blood passes through the vein • skeletal muscles contra

Back

Preview of the back of card 3

Card 4

Front

The heart consists of: • Aorta (to body) • Pulmonary artery (to lungs) • Pulmonary veins (from lungs) • Left and right atrium • Left and right ventricle • Atrioventricular valves (separates the ventricles and atrium) • Semi-lunar valve (separates the

Back

Preview of the back of card 4

Card 5

Front

Phase 3: Diastole Atria and ventricles relax during diastole. • Elastic recoil lowers pressure in the atria and ventricles. • Blood under higher pressure in the arteries is drawn back towards the ventricles, closing • the semi-lunar valves. The coron

Back

Preview of the back of card 5
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