AQA Additional Science B2 Part 1

  1. Functions of cell organelles
  2. Specialised Cells
  3. Diffusion
  4. Tissues
  5. Organs
  6. Organ Systems
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Functions of Cell Organelles

Plant and Animal Cells

  • Nucleus -controls all the activities of the cell
  • Cytoplasm -liquid gel where all chemical reactions take place
  • Cell Membrane -controls the passage of substances in & out of the cell
  • Mitochondria -Where the energy is made for the cell
  • Ribosomes -where protein synthesisi takes place

Just Plants

  • Cell Walls -strengthens cell and gives it support
  • Chloroplasts -contains chlorophyll which absorbs light energy to make glucose
  • Permanant Vacuole -a space in the cytoplasm filled with cell sap 

 

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Specialised Cells

There are many types of animal and plant cells. As an organism matures, each cell develops into a particular type. 

The structure of the cell is linked to its function;

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      • If a cell has many mitochondria it must need a lot of energy e.g. muscle cell etc.
      • If cell has many ribosomes it is making a lot of protein, e.g. gland cells which produce enzymes
      • Cells with tails are able to move, e.g.sperm cells
      • Root Hair Cells increase surface area to absorb water and mineral ions efficiently 
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Diffusion

  • Diffusion is the spreading out of particle of gas, or of any substance in solution
  • The Net Movement into or out of cells depends on the concentration of particles on each side of cell membrane
  • Difference in concentration between 2 areas in concentration gradient
  • larger difference = faster rate of diffusion
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Examples of Diffusion

  • Diffusion of oxegen into the cell of the body from the bloodstream as the cells are respirng (and using up oxegen
  • Diffusion of Carbon Dioxide into actively photosynthesising plant cells
  • Diffusion of sipmle sugars and amino acids from the gut through cell membranes
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Tissues

A tissue is a group of cells with similar structure and function

Animal tissues include; 

  • Muscle tissue - contracts to bring about movement
  • Glandular tissue - produces substances such as enzymes & hormones
  • Epidermal tissue - covers parts of the body

Plant tissues include;

  • Epidermal tissue - covers the plant
  • Mesophyll - can photosynthesise
  • Xylem & Phloem - transport substances around the plant
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Organs

Organs are made of tissues

The Stomach organ is made from;

  • muscular tissue to churn the stomach contents
  • glandular tissue to produce digestive juices
  • epithelial tissues covers the inside & outside of the stomach

The leaf, stem, and root are plant organs which contain epidermal tissues, mesophyll, xylem and phloem.

  • groups of organs form organ systems to perform a particular function
  • the digestive system has several organs, including the small intestine
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Organ Systems

Groups of organs work together in an organ system

Digestive system is a muscular tube which includes;

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      • glands, such as the pancreas and salivary which produce digestive juices
      • the stomach and small intestine where digestion occurs
      • liver which produces bile
      • the small intestine where aborbtion of soluble food occurs
      • the large intestine is where water is aborbed from undigested food, producing faeces
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Comments

narut


This is the one I was searching for thanx

Devan Ghatole

Exactly what i needed. this is basically my notes which are pages long in a short and simple form. nothing key has been missed out thanks so much

haider.s

seems good

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