Topic 1 lifestyle, health and risk

What are the 4 components in blood and what do they each do?

Red blood cells-carry and transport oxygen around the body by bonding with the haemoglobin.

White blood cells-defend the body against pathogens as part of the immune system.

Platelets-Mediate blood clotting to prevent blood loss and seal wounds.

Plasma-Act as the liquid transport medium that carries cells, dissolved nutrients, hormones, and waste.

Why is water a good solvent?

Water molecules from a layer around the ions and break the ionic substance apart through hydrogen bonds.

What does hydrophilic and hydrophobic mean?

Hydrophilic-water loving

Hydrophobic-water hating

What is the definition of specific heat capacity?

The amount of energy needed to raise the temperature of 1cm3 by 1 degree celsius.

What is cohesion and adhesion?

Cohesion-the attraction between water molecules.

Adhesion-the attraction between water molecules and other molecules.

What is mass flow?

Movement of fluids down a pressure gradient from an area of high pressure to low pressure.

Why do organisms require a mass transport system?

Larger animals have a smaller surface area to volume ratio and a higher metabolic rate. Diffusion alone is insufficient to supply all cells with in the substances they need.

Describe the function of the heart's major blood vessels

Vena cava= brings oxygenated blood from the body to the heart.

Pulmonary artery= takes blood from the heart to the lungs.

Pulmonary vein= brings oxygenated blood from the lungs to the heart

Aorta= takes blood from the heart around the body.

Relate the structure of arteries to their function.

Thick muscular walls to handle high pressure without tearing. Elastic tissue allows recoil. Narrow lumen to maintain pressure

Relate the structure of veins to their function.

Thin walls due to low pressure. Require values to ensure blood doesn't flow backwards. Have less muscular and elastic tissue as they don't have to control blood flow,

Relate the structure of capillaries to their function

Walls only one cell thick for a short diffusion pathway. Very narrow so that permeate tissues and red blood cells can lie flat against the wall, effectively delivering oxygen to tissues

Describe what happens during cardiac diastole

The heart is relaxed. Blood enters the atria, increasing the pressure and pushing open the atrioventricular valves. This allows blood to flow into the ventricles. Pressure in the heart is lower than in the arteries, so semilunar valves remain closed.

Describe what happens during atrial systole.

The atria contracts, pushing any remaining blood into the ventricles.

Describe what happens during ventricular systole.

The ventricle contracts. The pressure increases, closing the atrioventricular valves to prevent back flow, and opening the semilunar valves. Blood flows into the arteries.

Differentiate between correlation and causation

Correlation= Where a change in one variable occurs at the same time as a change in another variable.

Causation= Where a change in one variable causes a change in another variable

Give features of a good scientific study.

• Representative sample.

• Clear aim or hypothesis.

• Valid and reliable results.

• Controlled variables.

Give an ethical issue surrounding the use of invertebrates in research.

Some consider it wrong to harm other living organisms however some argue that they are not complex organisms so shouldn’t suffer with pain.

Definition for metabolism.

The total of all chemical reactions that take place within the cells of a living organism.

Why is Daphnia a suitable organism when investigating the effect caffeine has on heart rate?

• Transparent so the heart is visible underneath a microscope.

• Simple nervous system- unlikely to feel pain.

• Large surface area to volume ratio- Caffeine solution can be absorbed through skin.

What do reliability and validity mean?

Reliability- Getting consistent results each time the activity is repeated by the same person, using the same equipment, under the same conditions.

Validity- How well an experiment or measurement tests what it claims to test. Use of control variables and a control are necessary for validity.

What is blood pressure and what is the medical diagnosis for this?

Blood pressure is the force of your blood pushing against the walls of your arteries as your heart pumps it through your body.

Medical diagnosis- Hypertension ( drugs used for this are antihypertensives)

What is oedema?

The swelling of tissues caused by an abnormal accumulation of tissue fluid in the intercellular spaces.

Definition of a condensation reaction

Joining two molecules together by removing water, forming a chemical bond.

Definition of a hydrolysis reaction.

Splitting apart molecules through the addition of water, breaking chemical bonds.

Define the term monosaccharides

Single sugar molecules that act as a building block for more complex carbohydrates.

Define disaccharide.

Made of two monosaccharides joined together by a glycosidic bond. This is formed via a condensation reaction.

Define polysaccharide.

Large, complex carbohydrate made up of long chains of smaller sugar units (monosaccharides) linked together by glycosidic bonds.

what combination of monosaccharides are in the disaccharide sucrose?

Glucose + fructose

what combination of monosaccharides are in the disaccharide lactose?

Glucose + galactose

what combination of monosaccharides are in the disaccharide maltose?

Glucose + glucose

What is the difference between a 1,4 glycosidic bond and a 1,6 glycosidic bond?

A 1,4 glycosidic bond forms a straight, unbranched chain between sugar molecules, whereas a 1,6 glycosidic bond creates a branching point that leads to a complex, multi-directional structure.

Define triglyceride.

A lipid molecule formed by the condensation of a glycerol molecule and three fatty acid molecules.

Describe the difference in structure between a saturated fat and an unsaturated fat.

Saturated fats contain only single carbon (C-C) bonds between carbon atoms whereas unsaturated fats contain at-least one double carbon bond (C=C)

Compare the structure, role and CVD risk of HDLs and LDLs.

• Low density lipoproteins (LDLs)

-Formed primarily from saturated fats

-Transports cholesterol from the liver to body tissues/blood

-Excess LDLs saturates cell receptors, causing deposit is in damaged artery endothelium and forms atheromas.

• High density lipoproteins HDLs)

-Formed mainly by unsaturated fats.

-Transports excess cholesterol from tissues/blood to the liver.

-Removes cholesterol from plaques, liver breaks it down for excretion in bile.

Why are lipoproteins necessary for transporting cholesterol?

Cholesterol and lipids are non-polar/hydrophobic so cannot dissolve in the polar water molecules in the blood plasma, therefore lipoproteins act as a transport vehicle.

Explain how atherosclerosis leads to cardiovascular disease.

• The lumen narrows, restricting blood flow.

• This increases resistance in blood flow, elevating blood pressure further.

• Downstream tissues receives less oxygen and glucose for aerobic respiration and therefore the tissue dies.

  
  

What is atherosclerosis?

The hardening and narrowing of the arteries caused by the build-up of fatty deposits called atheromas inside the artery wall.

How does the structure of triglycerides make them ideal for long-term energy storage?

• High energy density: High ratio of C-H bonds to carbon atoms releases twice as much energy per gram as carbohydrates.

• Osmotic neutrality: They are large, non-polar, and insoluble, so they don't alter cell water potential or cause osmotic water movement.

• Low mass-to-energy ratio: Packs maximum energy into a lightweight mass, making it ideal for animal mobility.

What is an ester bond and how is it formed?

• Triglycerides are formed by esterification

• An ester bond forms when a hydroxyl (-OH) group from glycerol bonds with the carboxyl (-COOH) group of the fatty acid

  • The formation of an ester bond is a condensation reaction

  • For each ester bond formed a water molecule is released

  • Three fatty acids join to one glycerol molecule to form a triglyceride

  • Therefore for one triglyceride to form, three water molecules are released

Compare and contrast the structures of trehalose and maltose.

• Both are formed from two molecules of glucose

• Both contain a glycosidic bond

• Maltose has a 1-4 linkage whereas trehalose has a 1-1 linkage

Explain how the structures of amylopectin and glycogen make them suitable for storing energy.

• Branched therefore can be rapidly hydrolysed

• Compact so more energy can be stored

• Insoluble therefore does not affect osmosis

• Molecules too large to diffuse cell surface membrane

Compare and contrast the structure of a disaccharide with glycogen.

Similarities

• Both contain hydrogen, carbon and oxygen

• Both contain glycosidic bonds

• Both contain glucose

Differences

• Glycogen contains 1-4 and 1-6 glycosidic bonds whereas disaccharides only contain one type of glycosidic bond

• Glycogen contains only glucose whereas disaccharides can contain glucose and other monosaccharides.

Describe the structure of an unbranched polysaccharide.

• Polysaccharide made up of many monosaccharide components

• Joined together by glycosidic bonds

• Only 1-4 glycosidic bonds present- no 1-6 glycosidic bonds

How does blood clotting occur when a blood vessel is damaged?

1. Damage to the blood vessel causes platelets to become activated and release clotting factors.

2. Clotting factors cause prothrombin to be converted into thrombin.

3. Thrombin catalyses the conversion of soluble fibrinogen into insoluble fibrin.

4. Fibrin forms a mesh of fibres around the wound.

5. Red blood cells and platelets become trapped in the fibrin mesh, forming a blood clot.

6. The clot seals the wound, preventing further blood loss and reducing the entry of pathogens.