Investigate the structures of animal and plant cells and relate them to their functions


Nucleus Contains chromosomes which control the cell

Cytoplasm A liquid in which many cell reactions take place

Cell Membrane Holds the cytoplasm in place and allows certain substances into and out of the cell


Chloroplasts Carries out photosynthesis*

Vacuole Stores materials in water and supports the cell, animal cells can have vacuoles too, but they are less common and much smaller

Cell Wall Provides strength and support

*Photosynthesis is when a plant makes food from Carbon Dioxide in light.

All living organisms (the official way to say living things) are made up of cells. The most basic organisms have only one cell but most of the organisms you know are multi-celled (they have more than one cell).

So you should notice that all cells have

  1. a nucleus, this contains genes and DNA
  2. a cell membrane
  3. cytoplasm

they all carry out the processes of living things such as

  1. respiration
  2. growth

Cells are very small, many times smaller than a grain of sand....

how many grains of sand would you need to make a model of a human

so you would need many more cells to make you

To examine cells

Parts of the Microscope

Eyepiece Lens: magnifies the image produced by the objective lens. The usual level of magnification is 10X (magnified to make it look ten times bigger) The magnification is marked on the lens.

Nosepiece: allow different levels of magnification by allowing easy change to a different objective lens.

Objective Lens: magnifies the image of the object under study; the level of magnification is engraved onto the lens casing e.g. 4X, 10X, 40X. The 4X is the low power and the 40X the high power objective lens.

Coarse Focus Wheel: used for focusing at low power when using the low power objective lens.

Fine Focus Wheel: used for exact clear focusing producing the sharpest image at all levels of magnification; this is the only focus wheel to use with the medium and high power objective lens!

Stage: the glass slide is placed on the stage with the object for study it carries placed directly over the hole in the stage so light can pass through it; clips on the stage may be used to hold the slide in a steady position.

Light Source: this may be a reflecting mirror or a lamp below the stage.

Condenser: focuses the light from the light source onto the object on the slide.

Diaphragm: used to vary the amount of light passing to the object to get an image of the best clarity – not too bright or too dark.

The amount of magnification a microscope generates is found by multipling the magnification of the eyepiece by the magnification of the objective lens


cells, tissues, organs and systems,

relationship between cells, tissues, organs and systems

There are many different types of cells in living things, there are skin cells, blood cells, muscle cells ......

When the cells act together they are called a tissue

We are made up of billions of cells, as one cell is so small that we need a microscope to see it you can see that these cells must work together. Similiar cells all join to form tissue.

For example we are covered in skin, this skin is made up of billions of cells but all these cells are similiar to each other.

Under the skin, we have blood, bones and muscles these are all different substances, they too are made from cells, but the cells in bone and muscle are different.

When cells work together we call this tissue.

Each type of cell has its own function (job) in large multicelled organisms, here are a few examples of

the functions that cells carry out,

When different sets of tissues act together they are called an Organ

examples include

Kidney, Heart, Lungs, Skin, Brain, Intestines, Liver, Bladder, Stomach, Spleen, Appendix, Eyes.

When different Organs, Tissues and Cells work together they are called Systems.

examples include

  • Respiratory System
  • Circulatory System
  • Urinary System
  • Sensory System
  • Digestive System
  • Reproductive System

In this course we will deal with many different types of systems. Check the biology index page for examples of the different systems that the body needs to survive.

and when different systems work together it is an organism

Growth results from cell division

The details of what happens inside the nucleus come later in the section on genetics

Photo - Light

Synthesis - to make

Photo Synthesis - to make with light

Leaves are like solar cells for plants,

they take ___light and use that energy to make FOOD,

from _____ and ______ ______

Adenosine triphosphate (ATP) molecule is known in biochemistry as the "credit" of intracellular energy transfer;

ATP is able to store and transport chemical energy within cells

ATP also plays an important role in the synthesis of nucleic acids. Like D.N.A. (R.N.A.)

ATP is highly soluble in water

ATP is quite stable in solutions between pH 6.8 and 7.4

ATP can be produced by various cellular processes, most typically in mitochondria or in the case of plants in chloroplasts by photosynthesis.

The main fuels for ATP synthesis are glucose and fatty acids.

HW p 85 q 5 - 9

The total quantity of ATP in the human body is about 0.1 mole. The energy used daily by an adult calls for the hydrolysis of 200 to 300 moles of ATP. This means that each ATP molecule has to be recycled 2000 to 3000 times during the day. ATP cannot be stored and so its synthesis has to closely follow its consumption.


Adenosine triphosphate




nucleic acids