Sci Chap 15

Question 1

What is the human transport system called?

Answer 1

The circulatory system.

Question 2

What does the circulatory system consist of?

Answer 2

Blood, blood vessels, and heart.

Question 3

Define and describe blood and its components.

Answer 3

Blood is continuously circulated around the body, transporting many substances. Humans have about 5 litres of blood. Blood consists of 4 components:
1. Plasma
Transports water and dissolved substances such as digested food, mineral salts, and waste products to different parts of the body.

2. Red blood cells
Transports oxygen to different parts of the body and gives blood its red colour.

3. White blood cells
Protects the body against infections by engulfing bacteria and producing antibodies.

4. Platelets
Helps to form blood clots to prevent severe bleeding and prevents microorganisms from entering a wound.

The 4 components of blood can be separated using a process called centrifugation.

Question 4

Define and describe blood vessels and their components.

Answer 4

The blood vessels include:
1. Arteries
Typically carries oxygenated blood away from the heart and branches into capillaries.

2. Veins
Capillaries join to form veins. Typically carries deoxygenated blood towards the heart.

3. Capillaries
Acts as the site of exchange of substances such as digested food, oxygen, carbon dioxide, and waste substances. They have very thin walls for the exchange of substances to occur.

Question 5

Define and describe the heart.

Answer 5

The heart is a muscular pump. Its pumping action keeps the blood circulating around the body quickly and constantly.

Question 6

What is the plant transport system made up of?

Answer 6

Xylem tissue and phloem tissue.

Xylem:
- Transports water and mineral salts from the roots to all parts of the plant upwards.
- Located on the inner ring of the stem.

Phloem:
- Transports sugar from leaves to all parts of the plant upwards and downwards.
- Located on the outer ring of the stem.

Question 7

What are the processes involved in the transportation of substances?

Answer 7

Diffusion and osmosis.

Question 8

Define diffusion.

Answer 8

Diffusion is the net movement of particles (ions/molecules/atoms) from a region of higher concentration to a region of lower concentration. It can occur with or without a partially permeable membrane and does not require energy. Diffusion will occur until both regions are of the same/balanced concentration.

Question 9

Define osmosis.

Answer 9

Osmosis is the net movement of water molecules from a region of higher water potential to a region of lower water potential.

It is a type of diffusion, but it only involves the movement of water molecules. It can only across a partially permeable membrane. It only occurs when water molecules are in a liquid state.

Question 10

Explain osmosis in plant cells.

Answer 10

Water enters the roots by osmosis. The water molecules then move across from cell to cell by osmosis. They are then transported to the rest of the plant via the xylem.

When a plant cell is placed in a solution of higher water potential, the water molecules of the solution enter the cell by osmosis through a partially permeable membrane. The cell then expands in size and becomes turgid. However, the cell wall prevents the cell from bursting.

When a plant cell is placed in a solution of lower water potential, the water molecules of the cell sap leave the cell by osmosis through a partially permeable membrane. The cell membrane then pulls waway from cell wall and the cell becomes plasmolysed and becoms flaccid.

Question 11

Explain osmosis in animal cells.

Answer 11

When an animal cell is placed in a solution of a higher water potential, the water molecules of the solution enter the cell by osmosis through a partially permeable membrane. The cell will then burst/lyse.

When an animal cell is placed in a solution of lower water potential, the water molecules within the cytoplasm leave by osmosis through a partially permeable membrane. The cell then shrinks in size and becomes crenated.

Question 12

Why does our skin turn wrinkly after a long period of time in water?

Answer 12

When our skin is placed in water for a long time, the water has a lower water potential than the cytoplasm in our skin cells. Water molecules leave the skin cells by osmosis through a partially permeable membrane, moving from a region of higher water potential (inside the cells) to a region of lower water potential (the surrounding water). The cells shrink and become crenated, making the skin loose and appear wrinkled.

Question 13

To replenish his body fluids, a patient was accidentally given a large transfusion of distilled water directly into one of his veins. What may happen?

a. no undesirable effect as long as the water is sterile.
b. serious, perhaps fatal effects, because the red blood cells may become plasmolysed.
c. serious, perhaps fatal effects, because the red blood cells may become crenated.
d. serious, perhaps fatal effects, because the red blood cells may become lysed.

Answer 13

d

Question 14

What systems can drugs affect, and how?

Answer 14

Nervous system
- Poor balance and coordination
- Slower reaction
- Insomnia
- Anxiety
- Irritability
- Hallucination
- Memory loss

Circulatory system
- Increased heart rate
- Increased blood pressure
- Increased risk of heart attack and stroke
- Narrowed arteries, resulting in reduced blood flow to the limbs.

Respiratory system
- Lung cancer
- Emphysema (collapse of the walls of the tubes in the lungs)

Digestive system
- Nausea
- Increased risk of mouth and throat cancer
- Severe tooth decay
- Stomach ulcer
- Liver damage

Reproductive system
- Infertility

Question 15

What is an organ transplant, and what are its ethical considerations?

Answer 15

An organ transplant is a medical procedure carried out to replace a damaged organ. However, there are ethical considerations:

1. Respect for Persons
- Has the donor been given full info about the organ transplant to make his/her decision?

2. Justice
- What criteria are used to ensure fairness in the allocation of organs?

3. Minimal harm, maximised benefits
- What decisions will increase the chances of the patient’s survival?
- To what extent will the patient’s quality of life be enhanced?
- What alternative treatments are available to the patient waiting fr an organ transplant?
- Should age be a consideration when allocating an available organ to a potential recipient? Why?

Question 16

Explain diffusion in the human transport system.

Answer 16

The capillary of higher concentration of digested food and oxygen, and a lower concentration of waste substances and carbon dioxide, while the tissue cells have a lower concentration of digested food and oxygen, and a higher concentration of waste substances and carbon dioxide. Hence, diffusion occurs, with digested food and oxygen from the capillaries diffusing into the tissue cell from a region of higher concentration to a region of lower concentration, and waste substances and carbon dioxide diffusion from the tissue cell to the capillary from a region of higher concentration to a region of lower concentration.

Question 17

Explain diffusion in the plant transport system (gases)

Answer 17

The inside of a leaf contains a higher concentration of oxygen and a lower concentration of carbon dioxide than the outside. Hence, diffusion occurs, and oxygen from within the leaf diffuses out of the leaf and carbon dioxide from outsidee the leaf diffuses to the inside of the leaf as they move from a region of higher concentration to a region of lower concentration.

Question 18

Explain diffusion in the plant transport system (mineral salts)

Answer 18

Dissolved mineral salts diffuse from the soil into the root cells, from a region of higher concentration to a region of lower concentration. The minerals salts then diffuse from the root cells into the xylem, where they are transported to the rest of the plant.

Question 19

What is transpiration

Answer 19

Transpiration is the process by which water evaporates from the surfaces of plants, primarily through small pores called stomata on their leaves, stems, and flowers.

Question 20

Describe how water from the soil is absorbed by the roots and transported to the leaves of
the plant.

Answer 20

Root hairs take in water from the soil by osmosis. Water molecules diffuse from one root hair cell to another cell in the roots by osmosis to reach the xylem in the stem. Water is transported up to the leaves through xylem vessels, via transpiration pull.