How Organisms Grow Worksheet

You know quite a bit about cells, but what are they for - what do they do?

Lots of things, of course, but it's weird to consider that we humans are a great big bag of lots and lots of different cells, each working away to ensure that we are living, fully-functioning animals.

What happens when a cell gets old? How do we grow? Can things go wrong? These are the sorts of questions that we'll consider in this worksheet, so see what you can find out.....

When organisms - like a tree, a frog, a millipede, a daisy - grow bigger, what do you think is mainly going on to make this happen?

they are filling with water

their cells are growing bigger

they are stretching

their cells are multiplying

What is the process called by which organisms make more cells?

cell multiplication

cell division

cell addition

What name is given to the part of the cell that controls what happens in the cell and how the cell works?

cytoplasm

chloroplast

nucleus

What do you think the nucleus of the cell contains?

water

instructions

baby cells

When a cell is about to divide in two it does it in a certain order.

Here is a series of four diagrams - your job is to put them into the correct order by matching the diagram letter with the correct number of the order in which the changes occur.


A	B

C	D

Column A	Column B
1st	D
2nd	A
3rd	C
4th	B

Here is that sequence of diagrams again:


A	B

C	D

Diagram B shows two nuclei in one cell. What do you think has happened?

the nucleus has divided into two

the nucleus has copied itself

this happens when twins form

In a human, made up of billions of cells, the cells are dividing every day. Tick THREE reasons for this.

there needs to be a way of making cells smaller

some cells wear out, so new ones are needed

it's the way humans grow

it's the way the body repairs itself

new types of cell are made this way

In a plant, where do you think you would find an area where there are lots and lots of cells dividing?

in the flower petals

in the root tips

in the leaves

When a nerve cell divides, what sort of cells will form from it?

nerve cells

muscle cells

blood cells

If cells divide rapidly, often forming a mass of new cells that are a different sort or in the wrong place, this can lead to a condition known as:

cancer

Down's syndrome

arachnophobia

ANSWERS

Question 1

When organisms - like a tree, a frog, a millipede, a daisy - grow bigger, what do you think is mainly going on to make this happen?

CORRECT ANSWER

their cells are multiplying

EDDIE SAYS

Organisms grow by cell division - take a fertilised egg for example. What happens next? It divides into 2, then 4, then 8 and so on. By adding more and more cells, organisms get bigger until they reach their full size, like a lamb growing into a sheep or a sapling growing into an oak tree.

ANSWERS

Question 2

What is the process called by which organisms make more cells?

CORRECT ANSWER

cell division

EDDIE SAYS

A cell divides into two cells, which grow and then divide themselves - this is a process that continues throughout an organism's life.

ANSWERS

Question 3

What name is given to the part of the cell that controls what happens in the cell and how the cell works?

CORRECT ANSWER

nucleus

EDDIE SAYS

The nucleus is known as the \'control centre\' of the cell. In fact it contains an amazing chemical called DNA (which you\'ll learn about later) which is basically an incredibly long string of instructions. These instructions tell the cell what to do and how to do it.

ANSWERS

Question 4

What do you think the nucleus of the cell contains?

CORRECT ANSWER

instructions

EDDIE SAYS

The nucleus contains a long list of instructions (on the chemical DNA) which tell the cell what it is (like an eye cell, a nerve cell, a muscle cell, etc.) and how to carry out its functions. It\'s like a great big book of instructions all about how to make the cell work.

ANSWERS

Question 5

When a cell is about to divide in two it does it in a certain order.

Here is a series of four diagrams - your job is to put them into the correct order by matching the diagram letter with the correct number of the order in which the changes occur.


A	B

C	D

CORRECT ANSWER

Column A	Column B
1st	C
2nd	B
3rd	A
4th	D

EDDIE SAYS

OK, so first off there's a cell that's about to divide (C). Then the nucleus copies itself (B)(each new cell needs a full set of instructions) before the cell membrane divides (A) to make two new smaller cells, known as 'daughter' cells (D). These then grow to full size before dividing themselves.

ANSWERS

Question 6

Here is that sequence of diagrams again:


A	B

C	D

Diagram B shows two nuclei in one cell. What do you think has happened?

CORRECT ANSWER

the nucleus has copied itself

EDDIE SAYS

Each new cell needs a full set of the instructions that the nucleus contains, so the nucleus has the amazing ability to copy itself to make two complete nuclei. Then there's one for each of the new cells.

ANSWERS

Question 7

In a human, made up of billions of cells, the cells are dividing every day. Tick THREE reasons for this.

CORRECT ANSWER

some cells wear out, so new ones are needed
it's the way humans grow
it's the way the body repairs itself

EDDIE SAYS

Our cells are continually dividing, replacing worn out ones and also repairing bits of tissue that have been damaged. The other main reason for our cells dividing is to make us grow - mind you, that only continues until our late teens/early 20s.

ANSWERS

Question 8

In a plant, where do you think you would find an area where there are lots and lots of cells dividing?

CORRECT ANSWER

in the root tips

EDDIE SAYS

Plants grow from the tips of shoots and roots - these are the areas where you'll find masses of cells dividing rapidly, so that the root gets longer and longer, penetrating the soil for water.

ANSWERS

Question 9

When a nerve cell divides, what sort of cells will form from it?

CORRECT ANSWER

nerve cells

EDDIE SAYS

Nerve cells will only divide to form nerve cells - their nucleus has the instructions to make working nerve cells, so that is what will form when they divide.

ANSWERS

Question 10

If cells divide rapidly, often forming a mass of new cells that are a different sort or in the wrong place, this can lead to a condition known as:

CORRECT ANSWER

cancer

EDDIE SAYS

A tumour is a growth of rapidly dividing cells, many of which may split off and travel to other parts of the body in the blood, leading to new tumours forming. This results in cancer.