Which statement puts the blood vessels into increasing order of lumen diameter (interior diameter)?
capillary → artery → arteriole → aorta
arteriole → artery → capillary → aorta
aorta → artery → arteriole → capillary
capillary → arteriole → artery → aorta
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Which are chambers of the heart?
I. Atrium II. Aorta III. Ventricle IV. Lumen
I and III
I, II and III
III and IV
I and II
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Which shows the correct links between tissues within blood vessels and their modes of action?
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Which statement about the human circulatory system is FALSE?
The double circulatory system is a closed loop.
In the double circulatory system, blood passes through the heart twice on each full circuit of the body.
Blood bathes the cells in each organ that it is supplied to.
The systemic circulation loop supplies blood to all the major body organs including the brain.
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Which describes the sequence of chambers and vessels through which blood flows after it has left the vena cava, on its way to the lungs?
right atrium → right ventricle → pulmonary artery → lungs
left atrium → left ventricle → pulmonary artery → lungs
right atrium → right ventricle → aorta → lungs
left atrium → left ventricle → pulmonary vein → lungs
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In plants, which two substances does the xylem carry primarily?
Water and sugars
Sugars and mineral ions
Water and mineral ions
Starch and mineral ions
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Which of the following is not a consequence of the transpiration stream in plants?
An increased rate of photosynthesis
Plants remaining upright
The plant retaining heat
Supply of mineral ions to plant tissues
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Which row of the table best summarises the interaction of water molecules during water uptake by a plant?
| Water molecules pulling each other up | Water molecules sticking to the xylem walls | Capillary action |
A | cohesion | adhesion | adhesion |
B | cohesion | cohesion | adhesion |
C | adhesion | adhesion | cohesion |
D | cohesion | cohesion | cohesion |
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Which row of the table gives the best summary of the conditions in which mineral ions are taken up by plant roots?
| Water potential in soil | Water potential in root hair cell cytoplasm | Transport mechanism |
A | High | Low | Water channels across membrane |
B | Low | High | Transporter proteins |
C | Low | Low | Via membrane bilayer |
D | High | Low | Transporter proteins |
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The movement of phloem sap is an active process.
Which of the following is the most suitable explanation for this?
Phloem sap flows from the source to the sink.
ATP is required to load organic compounds into the phloem at the source.
Water leaves the phloem sieve tube at the sink.
Water moves into the phloem at the source by osmosis.
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Which of the following is not a structural feature of phloem tissue?
Lignified cell walls to withstand the hydrostatic pressure.
Columns of sieve tube cells.
Companion cells containing cell components that facilitate the loading and unloading of organic compounds.
Sieve plates with pores allows for the continuous movement of organic compounds.
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The micrograph below shows part of a cross section of a plant stem.
Which of the structures A-D represents the xylem tissue?
Image courtesy of Doc. RNDr. Josef Reischig, CSc. Licensed under Creative Commons Attribution-Share Alike 3.0 Unported license. Reused and distributed under conditions found at: https://creativecommons.org/licenses/by-sa/3.0/
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Which row correctly identifies a structure and its related function in a companion cell?
| Structure | Function |
A | Many mitochondria present | Translation of polypeptides that will form cell surface membrane proteins |
B | Nucleus and cell organelles | Carrying out the cell processes of the sieve tube cells |
C | Plasmodesmata | Linking adjacent companion cells with each other |
D | Small amount of cytoplasm present | Facilitating the movement of assimilates |
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The image below shows two structures commonly found in mammals. A light microscope was used to view the sample.
Identify the structures labelled X and Y along with one correct feature of these structures.
| X | Y | Feature |
A | Vein | Artery | Y contains deoxygenated blood |
B | Trachea | Artery | the lumen of X allows air to pass through |
C | Artery | Vein | Y contains many cells filled with oxyhaemoglobin |
D | Artery | Vein | X contains many cells filled with oxyhaemoglobin |
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The table gives the features of three blood vessels in the mammalian circulatory system.
Vessel 1 | Vessel 2 | Vessel 3 |
Thin layer of smooth muscle with few elastic fibres | Thick layer of elastic fibres and smooth muscle | No elastic fibres or smooth muscle |
What are vessels 1, 2 and 3?
| Vein | Capillary | Artery |
A | 3 | 2 | 1 |
B | 1 | 3 | 2 |
C | 2 | 3 | 1 |
D | 1 | 2 | 3 |
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The graph below shows the pressure in different parts of the heart during one cardiac cycle.
At which point does the semilunar valve of the aorta close?
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The diagram below shows the heart and associated blood vessels.
Which of the following would be correct for the flow of blood through the heart?
4 → 3 → 2 → 1
3 → 4 → 2 → 1
2 → 1 → 4 → 3
1 → 2 → 3 → 4
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The graph below shows the pressure in different parts of the left side of the heart during one cardiac cycle.
At the end of which section in the graph (A, B, C or D) would the ventricle be full of blood?
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The diagram below shows two cardiac cycles of a patient. The events of the cycle are placed next to a timescale.
What is the patient’s heart rate in beats per minute?
80
60
120
65
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The diagram shows a fault in the wall of the atria.
Which of the following would describe the effect of this fault?
Irregular heartbeat.
Ventricular systole is delayed.
Increased pressure in the pulmonary artery.
Reduced oxygen saturation of haemoglobin.
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Which of the following is not a contributing factor of atherosclerosis formation?
Damage to the endothelium of the arteries.
The circulation of unsaturated fats in the bloodstream.
High blood pressure in the arteries.
Build-up of atheromas under the endothelium.
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When a very narrow glass tube known as a capillary tube is dipped into water, water can flow up the tube despite the opposing force of gravity.
What is this model demonstrating?
Translocation
A hydrostatic pressure gradient
Cohesion between water molecules
Adhesion between water molecules
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The following steps describe the process of transpiration.
Water is drawn from xylem vessels to replace the water lost
A pulling force is transmitted throughout the xylem vessels all the way down the stem of the plant and to the ends of the xylem in the roots
Water evaporates from the surfaces of cells inside a leaf
A low pressure is generated within the xylem
What is the correct order of the steps?
III → II → IV → I
III → I → IV → II
I → III → IV → II
I → IV → III → II
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Which of the following relates to xylem vessels?
Transport organic compounds from source to sink
Transport mineral ions from roots to leaves
Provides mechanical support to the plant
Closely associated with companion cells to assist with loading of sucrose
I only
II and III only
I, II and III
III and IV only
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A student drew a diagrammatic representation of a transverse section of a plant stem based on what they saw using a light microscope.
Identify the correct labels required for the drawing above.
| I | II | III | IV | V |
A | Vascular bundle | Pith | Phloem | Cambium | Xylem |
B | Phloem | Xylem | Vascular bundle | Cambium | Pith |
C | Vascular bundle | Xylem | Pith | Cambium | Phloem |
D | Vascular bundle | Cambium | Pith | Xylem | Phloem |
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When water is taken up by roots, what process is responsible for this and what is the cause behind this process?
| Process | Cause |
A | Cohesion | The concentration of solutes in the soil is higher than in the roots |
B | Cohesion | The concentration of solutes in the soil is lower than in the roots |
C | Osmosis | The concentration of solutes in the soil is higher than in the roots |
D | Osmosis | The concentration of solutes in the soil is lower than in the roots |
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Identify the process by which mineral ions in soil move towards the root cell membrane.
Translocation
Transport through proteins known as protein pumps
Osmosis
Mass flow of water
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Which of the following correctly identifies a source and a sink in a plant?
| Source | Sink |
A | Sprouting potato tubers | Growing apples |
B | Growing apples | Sprouting potato tubers |
C | Young, growing potato tubers | Mature leaves |
D | Growing apples | Young, growing potato tubers |
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The following steps describe the process of translocation.
The solute concentration in the phloem sieve tubes increases
The increase in hydrostatic pressure causes phloem sap to flow towards sinks
Organic compounds are actively loaded into phloem sieve tubes
Water moves into phloem vessels by osmosis
What is the correct order of the steps?
III → II → IV → I
III → I → IV → II
I → III → IV → II
I → IV → III → II
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Which of the following statements apply to phloem sieve tubes?
They transport organic compounds from sink to source
They provides mechanical support to the plant
They are closely associated with companion cells to assist with loading of sucrose
They consist of living cells that form a continuous tube for the transport of phloem sap
I only
II and III only
I, II and IV
III and IV only
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Which of the following does not contribute to generating a high hydrostatic pressure at the source?
A high solute concentration in phloem sieve tubes due to the loading of sucrose
The incompressibility of water molecules
The rate at which sucrose is converted to starch in storage tissue
Rigid plant cell walls made of cellulose
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Girdling, or ring-barking, involves the removal of a strip of bark around the entire circumference of a tree trunk. This removes the outer part of the vascular bundles which results in the death of the entire tree over time.
What could be a possible explanation for this?
Xylem is removed from the vascular bundles, so water and mineral salts cannot be transported to the leaves
Phloem is removed from the vascular bundles, so sugars cannot be transported to the roots
Xylem is removed from the vascular bundles, so sugars cannot be transported to the roots
Phloem is removed from the vascular bundles, so water and mineral salts cannot be transported to the leaves
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The following photomicrograph shows the vascular bundle in a root.
Which letter identifies the phloem?
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A student studied the structure of a blood vessel and found:
An innermost layer of endothelial cells
A thick middle layer of smooth muscle and elastic tissue
An outer layer of collagen fibres
Which vessel was the student studying?
Vein
Capillary
Venule
Artery
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The aquatic crustacean the water flea (Daphnia magna, pictured below) has a heart that pumps blood-like liquid called hemolymph around its body cavity, once for every complete circuit.
Which statement about Daphnia magna's circulatory system is correct?
single closed
single open
double closed
double open
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The graph shows changes in pressure at various stages of the cardiac cycle.
Which statement describes the events at point Y of the graph?
Ventricular systole
The ventricle contracts
↓
Pressure in the left ventricle goes higher than in the aorta
↓
Aortic valve opens and blood is forced into the aorta
Early diastole
Left ventricle is empty
↓
Muscles in the walls of the left ventricle relax and pressure drops below the pressure in the aorta
↓
Aortic valve closes
Diastole
The relaxed left atrium fills with blood, causing the pressure in the atrium to exceed that in the empty ventricle
↓
The AV valve opens
Late diastole
There is a short period of time during which the left ventricle expands due to relaxing muscles
↓
This increases the internal volume of the left ventricle and decreases the ventricular pressure
↓
At the same time, blood is flowing slowly through the newly opened AV valve into the left ventricle, causing a brief decrease in pressure in the left atrium
↓
The pressure in both the atrium and ventricle then increases slowly as they continue to fill with blood
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Which is not a feature of the sinoatrial node (SAN)?
It acts as a natural pacemaker
It is formed from a group of highly specialised muscle cells
It occupies the area between the right atrium and the right ventricle
It sends out a wave of electrical activity, causing contraction, across both atria and both ventricles
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Which of these is not a function of plasmodesmata in plant cells?
To allow movement of water via the symplast pathway
To enable cell recognition
To allow communication between cells
To allow movement of nutrients between cells
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Which of the following best describes the factor that determines the direction of mass flow of phloem sap between leaves and fruit?
The active loading of sucrose into phloem sieve tubes near the fruit will create a hydrostatic pressure gradient that will facilitate mass flow between the leaves and fruit.
The movement of water molecules in the phloem sieve tubes from the leaves to the fruit will contribute to the hydrostatic pressure gradient between them.
The movement of organic compounds into the phloem sieve tubes near leaves will increase the hydrostatic pressure in the sieve tubes and create a pressure gradient between leaves and fruit.
The unloading of organic compounds from the phloem sieve tubes at the fruit will increase the osmolarity of the sieve tubes and create a hydrostatic pressure gradient between the leaves and fruit.
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