Year 8 Cells And Organisation - Mr. Hung 2014

1. Which are the building blocks of us?

Tissues

Organs

Cells

Systems

Level of Organisation
cells --> tissues --> Organs --> Systems --> Organism

Explanation

Level of Organisation
cells --> tissues --> Organs --> Systems --> Organism

2. Which organelle is NOT found in animal cells?

Chloroplast

Cell membrane

Nucleus

Cytoplasm

A plant cell has extra structures: cell wall, large vacuole and chloroplasts

Explanation

A plant cell has extra structures: cell wall, large vacuole and chloroplasts

3. Which structure is responsible for controlling substances to come in or go out?

Nucleus

Cytoplasm

Cell membrane

Vacuole

The cell membrane is responsible for controlling substances to come in or go out of the cell. It acts as a barrier, allowing only certain substances to pass through while blocking others. This selective permeability ensures that the cell maintains its internal environment and regulates the movement of molecules and ions in and out of the cell.

Explanation

The cell membrane is responsible for controlling substances to come in or go out of the cell. It acts as a barrier, allowing only certain substances to pass through while blocking others. This selective permeability ensures that the cell maintains its internal environment and regulates the movement of molecules and ions in and out of the cell.

4. Which structure is the Vacuole?

A

B

D

F

The correct answer is A because the vacuole is a membrane-bound organelle found in the cells of plants and some protists. It is typically the largest organelle in the cell and is responsible for storing water, nutrients, and waste products. It helps maintain the cell's shape and turgor pressure, and also plays a role in regulating the cell's pH and ion balance.

Explanation

The correct answer is A because the vacuole is a membrane-bound organelle found in the cells of plants and some protists. It is typically the largest organelle in the cell and is responsible for storing water, nutrients, and waste products. It helps maintain the cell's shape and turgor pressure, and also plays a role in regulating the cell's pH and ion balance.

5. The following shows the structures of a sperm. Why does this sperm have a lot of mitochondria?

To conserve water

To produce chemical for fertilisation

To produce energy for swimming

To prevent the tail from breaking

The sperm has a lot of mitochondria to produce energy for swimming. Mitochondria are the powerhouses of the cell and generate ATP, which is the main source of energy for cellular activities. Swimming requires a lot of energy, and the mitochondria in the sperm provide the necessary ATP for the tail to move rapidly and propel the sperm towards the egg.

Explanation

The sperm has a lot of mitochondria to produce energy for swimming. Mitochondria are the powerhouses of the cell and generate ATP, which is the main source of energy for cellular activities. Swimming requires a lot of energy, and the mitochondria in the sperm provide the necessary ATP for the tail to move rapidly and propel the sperm towards the egg.

6. Chloroplasts can't be found in cells of

Leaves

Roots

Green stems

Flower buds

Chloroplasts are organelles found in green parts of the plants. Chloroplasts actually consist of a green pigment called Chlorophyll that is important for the plant to make its own food by Photosynthesis. Roots are underground and they are not exposed to Sunlight.

Explanation

Chloroplasts are organelles found in green parts of the plants. Chloroplasts actually consist of a green pigment called Chlorophyll that is important for the plant to make its own food by Photosynthesis. Roots are underground and they are not exposed to Sunlight.

7. Which of the following is a tissue?

Heart

Digestive system

Skin

Muscle

There are 4 types of tissues: epithelial tissues, muscular tissues, nervous tissues and connective tissues,
Connective tissues include blood, ligaments and tendons. Skin is the largest organ in the body.

Explanation

There are 4 types of tissues: epithelial tissues, muscular tissues, nervous tissues and connective tissues,
Connective tissues include blood, ligaments and tendons. Skin is the largest organ in the body.

8. The image shows some ___________ cells.

Red blood cells

Nerve cells

Muscle cells

Cheek cells

Red blood cell is red without a nucleus. Nerves cell is elongated with extensions, muscle cell is long and pointed at the ends.

Explanation

Red blood cell is red without a nucleus. Nerves cell is elongated with extensions, muscle cell is long and pointed at the ends.

9. The following is a photomicrograph of young root. What can you see in these root cells?

Mitosis

Meiosis

Formation of pollens

Death of cells

The darker structures are chromosomes. There are various stages of cell division - mitosis.
Meiosis is a cell division for the formation of sex cells, eg. pollens and ovules in flowers or sperms and eggs in animals.

Explanation

The darker structures are chromosomes. There are various stages of cell division - mitosis.
Meiosis is a cell division for the formation of sex cells, eg. pollens and ovules in flowers or sperms and eggs in animals.

10. The image shows a Paramecium. Which is not a correct description of this organism?

A protozoan

A unicellular organism

A specialised cell of a multicellular organism

An animal-like single celled organism

The image shows a Paramecium, which is a unicellular organism. It is not a specialised cell of a multicellular organism because it is a complete organism on its own. Paramecium belongs to the group of protozoa, which are animal-like single-celled organisms.

Explanation

The image shows a Paramecium, which is a unicellular organism. It is not a specialised cell of a multicellular organism because it is a complete organism on its own. Paramecium belongs to the group of protozoa, which are animal-like single-celled organisms.