Cell Biology

1) What is an Organism ?
It is another word for something that is a living thing.

2) What are organisms made up of ?
They are made up of cells (which can only be seen under a microscope).

3) What are the different parts of cells called ?
Subcellular structures.

4) What are the two different cell categories ?
Prokaryotic - bacterial (simple structure)
Eukaryotic - animal, plant, fungal (complex structure)

5) Can you describe the difference between these two categories ?
Prokaryotic cells are much smaller in size (0.002mm long)
Prokaryotic cells are single cell organisms
Prokaryotic cells do not have a nucleus
Prokaryotic cells do not contain a mitochrondia or chloroplasts

6) What are the different types of Cells ?
Animal, Plant and Bacterial.

7) Can you describe the different parts of an Animal Cell ?
Nucleus - controls what the cell does, contains chromosomes made of DNA
Cytoplasm - the inside where the chemical reactions take place
Membrane - the skin that holds the cell together and controls what enters and leaves
Mitochondria - for aerobic respiration
Ribosomes - where the proteins are made

8) Can you describe the different parts of a Plant Cell ?
nucleus, cytoplasm, membrane, mitochondria
Cell Wall - outer layer around the membrane for extra support
Vacuole - the middle which is a sap liquid to maintain pressure and keep the cell rigid
Chloroplasts - for photosynthesis (not all plant cells, root cells do not receive light)

9) Can you describe the different parts of a Bacterial Cell ?
cytoplasm, cell wall
Flagella - tail like structures that allow movement
Plasmid - small rings of DNA
Chromosomal - the chromosome

10) What is a Multicellular Organism ?
An organism that is made up of lots of cells.

11) What is a Unicellular Organism ?
An organism that is made up of just one cell (eg Bacteria, Euglena, Amoeba).

12) What is a Micro organism ?
Micro organisms are organisms that can ony be seen with a microscope.
They include: bacteria, yeast, protozoa, algae, fungi, viruses.
Most are harmless to humans but a small number of them can cause diseases.

13) How do substances move in and out of cells, what is the process called ?
Diffusion - particles move from a high concentration to a lower concentration.
This is one way substances can enter and leave cells
Animal cells - oxygen and glucose diffuse through the membrane into the cell (more oxygen and glucose outside the cell)
Plant cells - carbon dioxide diffuses through the membrane out of the cell

14) What is Mitosis ?
Cells go through a series of changes involving growth and division

15) What is Osmosis ?
This is the diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane.

16) Can you describe the different parts of a flower ?
Leaves - carry out photosynthesis and create glucose/food
Stem - holds up the flower, connecting the root and leaves, transports water
Root - stabilizes and supports the plant, absorbs water and minerals and then transports it to the rest of the plant

17) Can you describe the different parts of a flower ?
Stamen - (male part), anther and filament, anther contains pollen grains
Carpel - (female part), stigm, style, ovary contains ovules
Petal - colourful and visible to attract insects
Sepal - green leaf parts, protect the flower when it is in bud
Ovary - when the lower dies the ovary decomes a fruit which contains the seeds

18) What are Stomata ?
These are very small holes in the leaf that allow carbon dioxide and oxygen to pass through

19) What is Pollination ?
This is the name of getting the pollen grains to the stigma

20) What is Nectar ?
Nectar is a sweet, sugary liquid that plants produce in special glands called nectaries, usually found in flowers.
Its main purpose is to attract pollinators such as bees, butterflies, birds.

21) Can you describe the two different ways pollination can take place ?
All plants can be grouped into two categories: flowering and non flowering.
Insects - seeds are sticky, have hooks to cling to animal fur
Wind - seeds are light and feathery or have wings

22) Can you describe Insect Pollination ?
Insects visit flowers to get food, when they are there the pollen sticks to them
When they travel to other flowers, the pollen travels with them.
Plants that are pollinated by insects have bright petals (to attract insects) and a sticky stigma.

23) Can you describe Wind Pollination ?
The anthers dangle outside the flower.
This allows the wind to detach the anthers and be blown away.
These flowers have a feathery stigma to catch the pollen as it blows past

24) What is Fertilisation ?
This is the joining of a male sex cell and a female sex cell to form the first cell of a new organism.

25) Can you describe the Fertilisation process for a plant ?
In a plant once the pollen lands on the stigma a pollen tube grows out from the pollen grain into the ovary.
The nucleus from inside the pollen grain moves down the tube.
It joins with the nucleus of the female sex cell inside the ovule.

26) What happens after Fertilisation ?
The ovule develops into a seed.
Each seed contains an embryo plant.
The ovary develops into a fruit around the seed.
The seed then needs to be distributed.

27) Can you describe the different ways seeds are dispersed ?
Wind - parachutes and wings
Animals - seeds are eaten and then poo'ed out
Explosions - pea pods
Gravity - drop and roll
Water - seeds float and are carried by rivers and streams

28) What is the name given to plant reproduction that does not need pollen or an egg ?
Asexual reproduction

29) Can you describe the reproduction process for most plants and animals ?
Pollen from one plant lands on the stigma of another
The pollen and the egg combine to make a seed
The seed grows into a seedling
The seedling grows into a plant.

30) Can you describe the different stages in a flower reproduction ?
Pollination
Fertilisation
Seed Production
Seed Dispersal

31) Where does all the energy come from ?
The Sun.

32) What do plants use the sun's energy for ?
To make food during photosynthesis.
They use the food to build molecules (like proteins) which become part of the plants cells.
These molecules store the sun's energy.
This energy gets passed on from plants to animals when the plants are eaten.
Animals need plants to carry out photosynthesis.

33) If there were no plants, would there be enough Oxygen ?
No. When plants and animals respire they take in oxygen and give out carbon dioxide.
During photosynthesis, plants take in carbon dioxide and give out oxygen.
Without plants there would be too much carbon dioxide in the air.
Without insects a lot of plants would not be able to pollinate.

34) What are Stem Cells ?
Cells are normally very specialised in their structure and function.
However some cells are undifferentiated which means that they can divide to make different types of cells.
These types of cells are called stem cells.

35) What are Chromosomes ?
The nucleus of a cell contains chromosomes that are made of DNA.

36) What are the reproductive organs in a human called ?
Male - Testicles produce sperm cells
Female - Ovaries produce egg cells

37) What is a Microscope ?
It can be used to see animal, plant and bacterial cells.
There are two types: light microscope and electron microscope.
An electron microscope gives much better resolution.

38) How do you use a microscope ?
Place the object on a slide.
Stain the sample
Cover the sample with a coverslip
Put the slide under the microscope
Illuminate and focus

39) A microscope has a magnification of x120
The height of the cell image is 1.5cm. Calculate the actual cell height ?

40) What is Resolution ?
The ability to see two or more objects as separate objects is called resolution

41) What is Magnification ?
The magnification is how many times larger the image is than the real object.
Magnification = (size of image) / (size of real object)