grade 7 - Blood and it`s components

Where are red blood cells made?

• Liver

• Bone marrow

• Brain

• Heart

Answer explanation

Red and white blood cells are made in the bone marrow. The brain controls your actions, the heart pumps blood around the body and bile is made in the liver.

Which cell component are red blood cells missing?

• Cell membrane

• Mitochondria

• Cytoplasm

• Nucleus

Answer explanation

Red blood cells are missing a nucleus. All cells have a cytoplasm, a membrane and mitochondria.

What moves into the blood in the lungs?

• Water

• Oxygen

• Carbon dioxide

• Nitrogen

Answer explanation

Oxygen moves into the blood in your lungs to be transported around the body. Carbon dioxide moves the other way, and usually so does water. Nitrogen is not absorbed into the body.

By which process does oxygen move from your red blood cells into cells?

• Osmosis

• Active transport

• Diffusion

• Respiration

Answer explanation

Oxygen moves from red blood cells by diffusion.

Osmosis is the diffusion of water across a membrane (into or out of a cell). Active transport moves substances the other way to diffusion. Respiration is the release of energy from glucose.

Which process in your cells requires oxygen to release energy?

• Protein synthesis

• Photosynthesis

• Digestion

• Respiration

Answer explanation

Respiration releases energy from glucose when reacting with oxygen.

Digestion breaks down food into nutrients. Photosynthesis stores the Sun's energy in glucose. Only plants and algae can do this. Protein synthesis is the manufacture of protein.

Which of these is not a type of white blood cell?

• Lymphocyte

• Phagocyte

• Erythrocyte

Answer explanation

Erythrocytes are red blood cells. 

Phagocytes are white blood cells that engulf pathogens. Lymphocytes are white blood cells that release antibodies.

True or false: There are more white blood cells than red blood cells in your body.

• true

• false

Answer explanation

It's false! There are many more red blood cells than white ones.

What is formed when platelets join together?

• Cholesterol

• Scars

• Scabs

• Tissues

Answer explanation

Platelets join together to form scabs.

Scars are formed after scabs when the skin has healed. Tissues are formed from cells. Cholesterol is a fatty substance within the blood.

True or false: White blood cells are part of your immune system.

• true

• false

Answer explanation

It's true! White blood cells attack invading pathogens as part of your immune system.

Which of these substances are not carried directly in blood plasma?

• Enzymes

• Hormones

• Oxygen

• Carbon dioxide

Answer explanation

Oxygen is carried in red blood cells in the plasma, unlike hormones, carbon dioxide and enzymes, which are carried directly in blood plasma.