Transportation in Animals and Plants – Important Questions & Answers

Circulatory System

Why do all organisms need a transport system?

All organisms need a transport system because:
- They need food, water, and oxygen to reach all parts of the body.
- Waste materials made in the body must be carried to places from where they can be removed.
What is blood?

Blood is a red coloured fluid that flows in blood vessels.
What are the functions of blood?

- It carries digested food from the small intestine to all body parts.
- It carries oxygen from lungs to body cells.
- It carries waste materials from cells to excretory organs (kidneys, lungs).
Why is our blood red in colour?

Blood is red because it contains a red pigment called haemoglobin in the red blood cells.
What is plasma?

Plasma is the fluid part of the blood in which different cells (RBC, WBC, platelets) are suspended.
Name the main parts of blood.

- Red blood cells (RBC) – carry oxygen
- White blood cells (WBC) – fight diseases
- Platelets – help in clotting of blood
- Plasma – fluid part of blood

What is heart? Where is it located?

- The heart is a muscular organ that pumps blood to all body parts.
- It is located in the chest cavity, slightly tilted towards the left side.
- The size of the heart is about the size of our fist.
What are the chambers of the heart? Why are they important?

The heart has four chambers:
- Two upper chambers: Atria (Right atrium and Left atrium)
- Two lower chambers: Ventricles (Right ventricle and Left ventricle)

Importance: The chambers keep oxygen-rich blood separate from carbon dioxide-rich blood.
Name and explain the three types of blood vessels.

- Arteries: Carry blood from the heart to body parts. They have thick walls. Most arteries carry oxygen-rich blood (except pulmonary artery).
- Veins: Carry blood from body parts back to the heart. They have thin walls and valves. Most carry carbon dioxide-rich blood (except pulmonary vein).
- Capillaries: Very thin vessels that join arteries to veins and help exchange food, oxygen, and waste between blood and tissues.
Why is pulmonary artery called an artery even though it carries carbon dioxide-rich blood?

Because it carries blood away from the heart, and all vessels carrying blood away from the heart are called arteries.

What is heartbeat?

- The rhythmic contraction and relaxation of the heart muscles is called heartbeat.
- It pumps blood continuously.
How can we hear heartbeat?

With the help of a stethoscope, a doctor can hear the sound of heartbeat more clearly.
What is pulse? How is it related to heartbeat?

- The throbbing movement felt in the arteries when blood is pumped is called pulse.
- Each heartbeat generates one pulse, so pulse rate = heartbeat rate.
What is the average heart rate in an adult human?

The average heart rate is about 70–80 beats per minute.
How do simple animals like sponges or Hydra transport food and oxygen?

- They do not have blood or circulatory system.
- Water around them brings in food and oxygen and removes wastes.

What is excretion?

The process of removal of waste products formed in cells of living organisms is called excretion.
What is the excretory system in humans? Name its parts.

The human excretory system removes dissolved wastes through urine. It consists of:
- Kidneys
- Ureters
- Urinary bladder
- Urethra
How do kidneys filter the blood?

- Blood reaches kidneys containing useful and harmful substances.
- Useful substances are absorbed back in blood.
- Harmful substances are removed as urine.
How much urine is normally passed by an adult human in a day?

An adult normally passes 1 – 1.8 litres of urine per day.
What is the composition of urine?

- 95% water
- 2.5% urea
- 2.5% other wastes
What is dialysis? When is it needed?

- Dialysis is the process of artificially cleaning the blood using a machine.
- It is needed when kidneys stop working due to disease or damage.
How do other animals excrete waste?

- Aquatic animals like fish – excrete wastes as ammonia into water directly.
- Birds, lizards, snakes – excrete a white semi-solid substance (uric acid).
- Humans – excrete urea in urine.
Apart from urine, how else does our body excrete waste?

Through sweat, which contains water and salts.
What other function does sweating have?

Sweating helps in cooling the body due to evaporation.

How do plants absorb water and minerals?

- Plants absorb water and minerals through root hairs.
- Root hairs increase surface area for better absorption.
What tissue helps in transport of water in plants?

- Xylem: It carries water and minerals from roots to stems and leaves.
What tissue helps in transport of food in plants?

- Phloem: It carries the food made in leaves to all parts of the plant.
What is transpiration?

- The process of loss of water as vapour from stomata (leaf pores) of plants is called transpiration.
What is the importance of transpiration?

- Helps pull water upward from roots to great heights (suction pull).
- Helps cool the plant.

Why is the heart compared to a pump?

Because like a pump, it works continuously to push blood to all parts of the body.
Why don't Hydra and sponges need blood?

They live in water. The surrounding water brings food and oxygen and carries away waste.
Why do veins have valves?

Valves allow blood to flow only in one direction – towards the heart.
Why do we see white patches on clothes after sweating?

Because salts in sweat get deposited after water evaporates.
Why do we keep vegetables like ladyfinger in water when they dry up?

Because water enters inside them through osmosis (absorption).