Movement in and out of cell

Diffusion

The net movement of molecules from a region of their higher concentration to a region of their lower concentration down a concentration gradient.This happens randomly due to the random movement of particles.

Diffusion is important to living organisms.–Photosynthesis–Respiration in humans–Scent from a flower to a bee.
Osmosis

The diffusion of water molecules  through a partially permeable membrane.A partially permeable membrane lets some molecule through but not others.Dilute solution to a concentrated solutionHigh water potential to a low water potential .

Cell membranes are partially permeable.The cytoplasm is always on side of the membrane.–The cytoplasm is a solution of proteins and other substances in water.The other side is the surrounding solution.
Osmosis in animal cells

Animal cell membranes can transfer water molecules through it but can not transfer other substances.In pure water the cell expands and can burst, or become hypotonic.
In a concentrated solution the shrinks and becomes hypertonic.Which way does water flow into the cell or out of the cell:–In pure water–In a concentrated solution



Osmosis in plant cells

Plasmolysed: is when the cell membrane, surrounding the cytoplasm, tears away from the cell wall.

     Requires a very concentrated solution and usually causes the death of the cell.

     The cytoplasm and vacuoles shrink as they lose water causes the cell membrane to tear away from the cell wall.

Active Transport

     The movement of ions in or out of a cell  through the cell membrane, but from a region of lower concentration to higher concentration.This is only possible because the cell must use energy to transport the ionsThis energy comes from where?

The movement of ions in or out of a cell  through the cell membrane, but from a region of lower concentration to higher concentration.This is only possible because the cell must use energy to transport the ionsThis energy comes from where?–From respiration

Carrier proteins: are special proteins on the cell membrane that transfer ions into the cell.These proteins change shape to transfer ions, but this change in shape takes energy.Some examples: guard cells in plants and humans small intestines transfer glucose

Cell structure

Cells

žAll living things are made of cells.žOrganisms that are single cells are called unicellular.Bacteria.
žMicroscopes

They are used to study cells.žLight microscopes shine light through animal or plant cells to make them visible.—Can magnify up to 1500 times.
—Only able to see some cell structures.ž
Scientist use a electron microscope to cells in great detail.—It uses electrons as a way to see cells and there parts.—Magnifies 500,000 times.
Cell Membrane

žAll cells have a cell membrane—It is a layer that surrounds the cellžInside the membrane is a substance called the cytoplasm, which surrounds the organelles.žOrganelles are a small structure in the cell.

Cell Wall

žPlant cells have a cell wall.žIt is made of cellulose fibers that crisscross each other.žThe spaces between the fibers makes the cell wall fully permeable, allows water and air through the layer.
Partially permeable membranes

žCell surface membrane or plasma membrane surrounds the cell.žIt is made up of proteins and fat.žIt has the important task of controlling what goes into and out of the cellThis is called partially permeable.
Cytoplasm

žIs made up of 70% water and other dissolved substances

žThis is where many metabolic reactions occur.

Vacuoles

žMost cells contain vacuoles or space in the cell surround by a membrane.žThey store substances for the cell—In plant cells it contains cell sap or a solution of sugar water—In animals it contains food and water .

Chloroplasts

žAn organelle that collects sunlight and makes energy from it.žFound in mostly in plantsžInside chloroplasts are chlorophyll that gives it a green pigment and is what absorbs the sunlight.—Chlorophyll contain starch grains—This is where photosynthesis occurs
Nucleus

ž  It stores the genetic information for the cell.

ž This information controls which proteins are made.

ž The genetic information is held on chromosomes that are made up of DNA.

Specialised cell

Specialised cell
Plants and animals consist of many cells and so are known as multicellular.
They contain many different types of cells.
Each type of cell is designed to carry out a particular job or function.
This is known as cell specialism. 
  Not all cells look the same. Some cells have special shape and features to help them do certain job.   

      Not all cells look the same.Some cells have a special shape and features to help them do a certain job.

      Sperm cell

     A sperm is small and has a long tail that provides movement so it can swim and find an egg cell.The head contains enzymes which allow it to digest into an egg cell and join with it.

Egg (Ovum) Cell

     Designed to be Fertilised.

     Found in the Ovaries.

     An egg cell is large and bulky.

    Contains yolk which provides a large food store for the new cell being formed.

Palisade Cell

Designed for PhotosynthesisFound in the top of a leaf Tall and has a large surface area to absorb water and minerals.
Packed with chloroplasts to help make plant food.

Ciliated Cell

  Designed to stop Lung Damage        They line all the air passages in the lungs.
They have tiny hairs called cilia.
Hairs sweep mucus with trapped dust and bacteria back up the throat.

            Root Hair Cell

Thin cell wall makes it easy 

for minerals to pass 

through.

Has a large surface which 

helps it to absorb water and 

minerals.

Found in a plant root.

Special features:

  long, thin cells arranged end-to-end to form vessels /tubes/. The cells lack end walls and cell contents such as cytoplasm and nucleus. The walls become lignified.

Function:

  transport water and mineral ions from roots to leaves. Lignin provides strength for the stem and makes the vessels waterproof

Nerve Cell (neurone)

They are long. 

They have connections at 

each end.

Can carry electrical signals 

Their job is to carry nerve 

impulses to different parts of the body.

Red Blood Cell

                                                                                                                   











Designed to carry oxygenFound in blood.Large surface area, for oxygen to pass through.Contains haemoglobin, which joins with oxygen.Has no nucleus

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