substance exchange - mass transport Flashcards

Question

flow of blood

Answer 1

flow of blood the blood is going to move from the right atrium thru the right av valve and into the right ventricle the its gonna move out thru the semilunar valve into the pulmonary artery (cos we're moving away from the heart) from the PA (PULMONARY ARTERY) we're going to the lungs in the lungs we pick up oxygen and were gonna return to the heart down the pulmonary vein from there were gonna enter the left side of the heart blood is gonna enter thru the left atrium thru the left av valve and into the left ventricle and from there we r gonna pass thru that semilunar valve and into the aorta and the aorta is gonna pump the blood right around the body where its gonna lose its oxygen and end up back at the vena cava from there we go back into the right atrium and the cycle repeats

Answer 2

flow of blood order ``` right atrium right ventricle pulmonary artery lungs pulmonary vein left atrium left ventricle aorta body vena cava ```

Answer 3

valves prevent back flow

Answer 4

whats the point of AV valves AV valves prevent blood from flowing back into atria when ventricles contract

Answer 5

whats the point of semilunar valves semilunar valves stop blood from flowing from arteries back into ventricles

Answer 6

blood wants to move from high pressure to low pressure when a chamber contracts, the pressure increases so blood could either move onto the next part of the heart or backwards: both r at low pressure valves prevent back flow

Answer 7

Vena cava The blood vessel that carries deoxygenated blood from the body into the heart. Renal artery The blood vessel that oxygenated blood flows through to enter the kidneys. Pulmonary vein The blood vessel that carries oxygenated blood from the lungs to the heart. Aorta The blood vessel that oxygenated blood flows out of the heart through and to the rest of the body. Coronary arteries The blood vessels that supply blood to the heart.

Answer 8

the cardiac cycle 1) Atrial contraction Blood from the lungs flows into the left atrium and blood from the body flows into the right atrium simultaneously. The atria contract, increasing the pressure in the atria. The blood in the atria is forced into the ventricles. The ventricles are relaxed and fill with blood.

Answer 9

the cardiac cycle 2) Ventricular contraction The atria relax and the ventricles start to contract. Contraction of the ventricles causes the pressure inside the ventricles to increase. The pressure shuts the atrioventricular valves so that blood does not flow back into the atria. The blood in the ventricles is forced out of the ventricles and out of the heart through the pulmonary artery or the aorta.

Answer 10

the cardiac cycle 3) Relaxation The blood in the pulmonary artery and the aorta is at high pressure. -The pressure shuts the semi-lunar valves so that blood does not flow back into the ventricles. Both the ventricles and the atria relax and the atrioventricular valves reopen. Blood flows into the ventricles and the atria from the pulmonary vein and vena cava.

Answer 11

the cardiac cycle

Answer 12

Right atrium Deoxygenated blood flows into the right atrium from the body. The vein that pumps deoxygenated blood into the right atrium is called the vena cava. The right atrium is the first chamber that deoxygenated blood flows through.

Answer 13

Right ventricle When the walls of the right atrium contracts, deoxygenated blood flows into the right ventricle. The atrioventricular valves prevent blood from flowing back into the atria from the ventricles. Then the walls of the right ventricle contracts, blood is pumped out of the pulmonary artery to the lungs. The semi-lunar valves prevent blood from flowing back into the right ventricle from the pulmonary artery.

Answer 14

Left atrium Oxygenated blood flows into the left atrium from the lungs. The vein that pumps oxygenated blood into the left atrium is called the pulmonary vein.

Answer 15

Left ventricle When the walls of the left atrium contracts, oxygenated blood flows into the left ventricle. The atrioventricular valves prevent blood from flowing back into the atria from the ventricles. The walls of the left ventricle are considerably thicker than the right ventricle. The left ventricle has to transport blood all the way around the body but the right ventricle only has to transport blood to the lungs.

Answer 16

Aorta When the left ventricle contracts, blood is pumped out of the heart to the rest of the body. Oxygenated blood leaves the heart through the aorta. The semi-lunar valves prevent blood from flowing back into the left ventricle from the aorta.

Answer 17

stages in the cardiac cycle contraction of the atria blood is forced into the ventricles contraction of the ventricles the AV valves shut blood is forced out of the heart the semi lunar valves shut the atria and ventricles relax

Answer 18

Pressure in the atria When the atria contract, the pressure in the atria increases. When the atria relax and the ventricles contract, the pressure in the atria decreases. When both the atria and the ventricles relax, there is a slight increase as the atria fill with blood again.

Answer 19

Pressure in the ventricles When the atria contract, the pressure in the ventricles is relatively low. There is a slight increase in pressure as the ventricles fill with blood. When the ventricles contract, the pressure increases dramatically. The pressure increases considerably more than when the atria contract. When both the atria and the ventricles relax, there is a slight increase as the ventricles fill with blood again.

Answer 20

Volume in the atria When the atria contract, the volume in the atria decreases. When the atria relax and the ventricles contract, the volume in the atria increases again. When both the atria and the ventricles relax, there is a slight decrease when blood flows into the ventricles from the atria.

Answer 21

Volume in the ventricles When the atria contract, the volume in the ventricles increases slightly as they fill with blood. When the ventricles contract, the volume decreases dramatically. The volume decreases considerably more than when the atria contract. When both the atria and the ventricles relax, the volume increases as the ventricles expand again.

Answer 22

Veins Veins transport blood back to the heart. The lumen of veins is wider than the arteries which allows the blood to flow at low pressure. There is a thin muscle wall and elastic tissue in the vein walls. Valves are located throughout the veins to ensure blood flows towards the heart.

Answer 23

Arterioles When arteries reach an organ, they split into many smaller vessels called arterioles. The direction of blood flow can be controlled by contracting the arterioles to restrict blood flow and relaxing the arterioles to allow blood to flow.

Answer 24

Arteries Arteries transport blood away from the heart to the organs. Artery walls have thick layers of muscle. The walls maintain a high pressure so blood can be pumped around the body. Elastic fibres in the artery wall allow the arteries to stretch. The endothelium is folded which also allows the arteries to stretch.

Answer 25

Features of veins: ``` 1 Wide lumen 2 Thin muscle wall 3 Elastic tissue in the walls 4 Valves to control blood flow ```

Answer 26

Artery walls have elastic fibres in the wall, allowing them to stretch and spring back (recoil).

Answer 27

Walls ``` Capillary walls (endothelium) are only one cell thick. This means that the diffusion distance of substances (e.g. oxygen) from the bloodstream to the tissues is very short. A short diffusion distance allows for efficient exchange. ```

Answer 28

Location Capillaries pass very close to the body cells. There is a very short diffusion distance between the capillaries and the body cells. Exchange between the capillaries and the body cells is rapid.

Answer 29

Surface area Arterioles split into millions of capillaries that can form networks around the body cells (e.g. the network around the alveoli). The networks create a large surface area for exchange of substances between the bloodstream and the tissues. Networks of capillaries are called capillary beds.

Answer 30

blood Vessels Veins Valves Wide lumen Capillaries Thin endothelium Capillary beds Arterioles Control blood flow Arteries High pressure Thick layers of muscle

Answer 31

Pressure filtration In order for the substances carried in the bloodstream (e.g. oxygen) to diffuse into the cells, they must first move out from the capillaries. Substances move into tissue fluid from the capillaries in a process called pressure filtration.

Answer 32

Steps Involved in Formation of Tissue Fluid fluid is forced out of the capillaries by pressure filtration

Answer 33

Deposition The endothelium of arteries can become damaged by the deposition of white blood cells and lipids. If white blood cells and fatty materials continue to be deposited in the artery walls, the materials will begin to form hard, fibrous plaque.

Answer 34

As the fibrous plaque builds up, the lumen of the artery becomes narrower. The flow of blood through the arteries is restricted. The narrower lumen also increases blood pressure. The presence of the fibrous plaque is called an atheroma.

Answer 35

Coronary heart disease Atheromas can cause diseases of the heart. Coronary heart disease (CHD) is a type of disease that is associated with many atheromas.

Answer 36

As fibrous plaque builds up, the artery lumen narrows. This restricts the flow of blood.

Answer 37

What causes the lumen of arteries to narrow in the formation of an atheroma? fibrous plaque

Answer 38

Atheromas can increase the risk of two types of diseases: Aneurysm & Thrombosis

Answer 39

Aneurysm Atheromas damage the artery walls and increase blood pressure. The increased blood pressure can cause the elastic fibres in the artery wall to swell in balloon-like structure. This swelling is an aneurysm.

Answer 40

Thrombosis Atheromas can damage the artery walls, causing them to burst open. Platelets are transported in the bloodstream to the damaged part of the artery wall. The platelets accumulate and form a clot called a thrombus. A thrombus can block blood flow in the artery.

Answer 41

Artery walls can burst open due to damage caused by atheromas. Platelets then accumulate and form a clot called a thrombus.

Answer 42

High blood pressure High blood pressure can be inherited or it can be caused by being overweight and consuming excessive alcohol. High blood pressure can contribute to the formation of atheromas.

Answer 43

Diet A diet that is high in saturated fat and salt can lead to high blood cholesterol levels. Cholesterol in the blood can contribute to the formation of atheromas in the arteries.

Answer 44

Smoking cigarettes increases the risk of high blood pressure. Carbon monoxide found in cigarettes reduces the amount of oxygen that can be carried by haemoglobin in the blood. Reduced transport of oxygen can increase the risk of a heart attack.

Answer 45

There are certain risk factors that can increase the chance of developing cardiovascular disease. These include: smoking diet high blood pressure

Answer 46

the walls of the left ventricle are a lot thicker as it has to pump blood around the whole body

Answer 47

Heart dissections allow the key features in the heart to be easily identified. Animal hearts can be sourced from the butcher. A larger heart allows ...

Answer 48

Which blood vessel should be sliced to open the heart? aorta

Answer 49

What apparatus is used for dissecting an animal heart? ``` 1 Sharp blades 2 Gloves worn throughout 3 Disinfectant or other antimicrobial liquid ```

Answer 50

Guidelines Gloves should be worn throughout dissection. Hands must be washed using disinfectant after dissection. Cuts should be made very carefully to avoid injury and allow you to see all the features.

Answer 51

Opening the heart The heart can be opened by slicing carefully from the aorta around the outside edge. Opening the heart allows you to view the ventricular walls and other internal structures. The valves can also be identified.

Answer 52

Ventricular walls Comparing the right and left ventricles shows that the left ventricular wall is much thicker than the right ventricle. This is a key feature of the heart.

Answer 53

The xylem are plant vessels that are responsible for transporting water and mineral ions. The structure of the xylem is specialised for this role.

Answer 54

Vessel elements The xylem vessels are long, tubes of cells that run up the stem of plants. The cells of the xylem are called vessel elements. The vessel elements in the xylem are dead.

Answer 55

End walls The vessel elements are stacked on top one another. There are no cell walls at the ends of each vessel element. This creates a continuous tube for water to flow through.

Answer 56

Lignin The walls of the xylem are lined with a waterproof polymer called lignin. Lignin reinforces the walls of the vessel elements to provide structural support.

Answer 57

Cohesion-Tension Theory ... travel up the xylem through ___ and ___. The steps involved in this process are: 1) Transpiration 2) Tension 3) Cohesion 4) Diffusion in the roots

Answer 58

1) Transpiration Some of the water in the leaves is used in photosynthesis. Most of the water in the leaves evaporates in a process called transpiration.

Answer 59

2) Tension The loss of water from the leaves creates tension in the xylem. Tension is the formation of hydrogen bonds between water molecules and the sides of the xylem vessel elements. Water in the xylem is pulled upwards by this tension towards the leaves.

Answer 60

3) Cohesion Individual water molecules also form hydrogen bonds with each other. This process is called cohesion. When water molecules are pulled up the xylem, other molecules of water are also pulled upwards due to cohesion. The combination of cohesion and tension together continuously pull water upwards to replace water that has been lost in the leaves by transpiration.

Answer 61

4) Diffusion in the roots When water is pulled up the stem, the water potential at the bottom of the plant decreases. Water diffuses into the roots via osmosis down its water potential gradient.

Answer 62

Investigating Mass Transport in Plants Mass transport can be investigated in two ways. Ringing tracing

Answer 63

Q1.(a) (i) Give two ways in which the structure of starch is similar to cellulose. polymers contain glycosidic bonds

Answer 64

(ii) Give two ways in which the structure of starch is different from cellulose. starch contains a glucose and has no h bonds between molecules

Answer 65

In plants, mass transport of sugars takes place through columns of sieve cells in the phloem. Other cells, called companion cells, transport sugars into, and out of, the sieve cells. The diagram shows the structure of phloem. Structures I and J allow the transport of sugars between cells. (i) Using the diagram, suggest and explain one other way in which sieve cells are adapted for mass transport. 1. few organelles 2. (So) easier flow

Answer 66

Using the diagram, suggest and explain one other way in which companion cells are adapted for the transport of sugars between cells. Mitochondria release energy (atp)

Answer 67

Q2.Organic compounds synthesised in the leaves of a plant can be transported to the plant’s roots. This transport is called translocation and occurs in the phloem tissue of the plant. (a) One theory of translocation states that organic substances are pushed from a high pressure in the leaves to a lower pressure in the roots. Describe how a high pressure is produced in the leaves. 1. Water potential becomes lower / becomes more negative (as sugar enters phloem) ; 2. Water enters phloem by osmosis; 3. Increased volume (of water) causes increased pressure.

Answer 68

https://pmt.physicsandmathstutor.com/download/Biology/A-level/Topic-Qs/AQA/3-Exchange-of-Substances/Set-B/Mass%20 PCMBS is a substance that inhibits the uptake of sucrose by plant cells. Scientists investigated the effect of PCMBS on the rate of translocation in sugar beet. The figure below shows their results. Time / minutes (b) During their experiment, the scientists ensured that the rate of photosynthesis of their plants remained constant. Explain why this was important. (b) 1. Rate of photosynthesis related to rate of sucrose production; 2. Rate of translocation higher when sucrose concentration is higher. (c) The scientists concluded that some translocation must occur in the spaces in the cell walls. Explain how the information in the figure above supports this conclusion.

substance exchange - mass transport Flashcards

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