Cells, Diffusion and Reproduction – Revision Flashcards

Forty-seven question-and-answer flashcards covering cell structure, specialised cells, tissues/organs, microscope parts, diffusion, cell division, genetics, and twins.

What are all living things made of?

Cells.

Why is a microscope needed to view cells?

Cells are very small and cannot be seen with the naked eye.

Which structure controls what substances enter and leave the cell?

The cell membrane.

In which types of cells is the cell membrane found?

Both plant and animal cells.

What jelly-like substance inside a cell is the site of most chemical reactions?

Cytoplasm.

Which organelle controls cell activities and carries genetic information?

The nucleus.

What is the site of photosynthesis in plant cells?

The chloroplast.

Which pigment found in chloroplasts absorbs light energy?

Chlorophyll.

Which organelle stores cell sap and helps keep plant cells firm?

The vacuole.

What tough carbohydrate makes up the plant cell wall and what is its function?

Cellulose; it supports and protects the cell.

What is the main function of a red blood cell?

To carry oxygen.

Name one adaptation of a red blood cell that increases oxygen transport.

It contains haemoglobin (or has a large surface area / lacks organelles).

What is the role of a nerve cell?

To carry nerve impulses around the body.

Give one feature that helps a nerve cell transmit signals.

Its great length (or branches at each end).

What is the function of an egg cell?

To fuse with a sperm cell and provide nutrients for the developing embryo.

Why do egg cells contain lots of cytoplasm?

To supply food/nutrients to the new zygote.

What is the function of a sperm cell?

To swim to and fertilise the egg cell.

Give one adaptation that helps a sperm cell reach the egg.

A long tail for swimming (or streamlined shape).

What is the job of a root hair cell?

To absorb water and minerals from the soil.

Why do root hair cells lack chloroplasts?

They are underground where there is no light for photosynthesis.

What is the function of a palisade (leaf) cell?

To absorb sunlight for photosynthesis.

Name one feature that helps a leaf cell photosynthesise efficiently.

It contains many chloroplasts (or has a large vacuole to keep the cell rigid).

Define a tissue.

A group of similar cells performing the same function.

Define an organ.

A structure made of different tissues working together to perform an important job.

Give an example of a plant organ.

A leaf.

Define an organ system.

Several organs working together to carry out a major body function (e.g., the digestive system).

Which microscope part contains the eyepiece lens?

The eyepiece.

What is the purpose of the nosepiece on a microscope?

It holds and rotates the objective lenses to change magnification.

What is the typical magnification range of microscope objective lenses?

Approximately ×10 to ×40.

What do stage clips do on a microscope?

Hold the slide in place.

Which knob moves the microscope stage up and down for coarse focus?

The coarse focusing knob.

Which knob slightly moves the stage to sharpen the image?

The fine focusing knob.

Define diffusion.

The movement of particles from an area of high concentration to an area of low concentration.

Name two substances that enter cells by diffusion.

Oxygen and glucose.

Which waste gas leaves cells by diffusion?

Carbon dioxide.

Why does the body need cell division?

For growth and to replace damaged cells.

What happens to cells that are damaged beyond repair?

They are destroyed and replaced with new cells.

Where is genetic information located within a cell?

In the nucleus.

How much genetic information does a body cell contain?

A full (complete) set.

How much genetic information does a sex cell contain?

Half of the full set.

What event restores a complete set of genetic information during reproduction?

Fertilisation, when sperm and egg combine.

How are identical twins formed?

One sperm fertilises one egg; the resulting zygote splits into two embryos.

Why do identical twins share the same characteristics?

They have exactly the same genetic information.

How are non-identical twins produced?

Two separate eggs are fertilised by two separate sperm.

Can non-identical twins be of different genders?

Yes.

Give an example of an organism that reproduces without sex cells.

Bacteria.