Biology B2 Unit 1

HideShow resource information

Animal 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.

1 of 6

Plant Cells

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

2 of 6

Specialised cells - part 1

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
3 of 6

Specialised cells - part 2

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

4 of 6

Diffusion & Osmosis

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

5 of 6

Osmosis (cont.)

  • 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
6 of 6


No comments have yet been made

Similar Biology resources:

See all Biology resources »See all Cells, tissues and organs resources »