Cells

Nucleus - controls all the activities within a cell. Also contains instructions for creating new cells

Cytoplasm - where all the chemical reactions needed for life takes place. This includes respiration

Cell membrane - controls the passage of substance in and out of the cell

Mitochondria - structures in the cytoplasm where most of the energy is released during respiration

Ribosomes - where protein synthesis takes place. All of the protein needed in the cell are made here.

All plants have the features of an animal cell and also:

Cell Wall - made of cellulose which strengthens the cell and gives it support.

Most plants cells also have:

Chloroplasts - contains chlorophyll which absorbs light energy to make food by photosynthesis

Permanent Vacuole - a space in the plant cell filled with cell sap that provides support support to make the plant rigid

Fat cell:

• Have a little amount of cytoplasm to leave room for fat
• Can expand 1000 times its size to contain the fat

Cone cell from human eye:

• Outer segment filled with visual pigment that changes chemically in coloured light which requires energy
• Middle segment filled with mitochondria to give energy for visual pigment change

Root hair cells:

• the root hair gives the cell a larger surface area for water to move in and out of cells
• has a large permanent vacuole which affects the movement of water

Sperm cell:

• long tail with muscle-like proteins to swim towards the egg.
• Middle section filled with mitochondria to power the tail
• Acrosome (located on the tip of sperm cell's head) contains digestive enzymes for breaking down the outer layers of the egg
• large nucleus contain genetic info for egg

Cells ------> Tissues ------> Organs ------> Organ Systems ------> Whole Body

Diffusion is the net movement of particles from an area of high concentration to an area of a lowER concentration by random movement of the particles

Osmosis is the movement of water from a high water concentration (dilute solution) to an area of lowER water concentration (concentrated solution) through a partially permeable membrane

• If the concentration of the solution around a cell in the body is lower than the concentration of substances inside the cell, water will enter the cell by osmosis
  • This makes the cell swell up, lose their shape and eventually burst 

• If the concentration of the solution around a cell in the body is higher than the concentration of substances inside the cell, water will leave the cell by osmosis
  • This makes it shrivel and shrink so it can no longer function