Scribd
Upload
9 views8 pages

Cells

A cell is the basic unit of life that is too small to see with the naked eye and requires a microscope. Plant and animal cells contain organelles that perform specialized functions like the cell wall, cell membrane, nucleus, mitochondria, and chloroplasts. Cells can be unicellular like bacteria and protozoa or multicellular and specialized like red blood cells, sperm cells, and neurons. Materials move into and out of cells through diffusion, osmosis, and active transport.

Uploaded by

Azariah Gobin
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
9 views8 pages

Cells

A cell is the basic unit of life that is too small to see with the naked eye and requires a microscope. Plant and animal cells contain organelles that perform specialized functions like the cell wall, cell membrane, nucleus, mitochondria, and chloroplasts. Cells can be unicellular like bacteria and protozoa or multicellular and specialized like red blood cells, sperm cells, and neurons. Materials move into and out of cells through diffusion, osmosis, and active transport.

Uploaded by

Azariah Gobin
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
You are on page 1/ 8

A cell is the basic unit of life

We need a microscope to see cells as we cannot see it with our naked eye due to
the fact that it is very small.

Plant cell

Animal cell
Organelles and their functions
Cell wall-prevents bursting of plant cell and gives it a fixed shape

Cell membrane-selectively permeable barrier which controls exchange between the


cell and its environment

Cytoplasm-site of many chemical reactions in life

Nucleus-controls activities of the cell,contains chromosomes

Chromosome-carries genetic information in the form of DNA

Mitochondrion- site of energy production

Vacuole-important during exchange of water and minerals,stores various substances


including waste products

Chloroplast-site where photosynthesis occurs

Difference between plant and animal cell


Unicellular microbes
-Viruses

These cause influenza,cold,measles,smallpox and HIV

-Bacteria
Bacteria decomposes dead organisms.They cause diseases such as cholera and
tuberculosis

Protozoa

This causes malaria and sleeping sickness.

Cell specialisation
Specialised or differentiated cells have specific tasks in multicellular organisms and
thus they have features and adaptations in order to assist in performing that task.

1.Red blood cells


-Transport oxygen and carbon dioxide
-have disc shape to allow oxygen to diffuse

Sperm cell

-Fertilises the egg


-Has a tail that allows it to swim

Neurone

-transports electrical messages through the body


-has branches that connect to other neurones
Epithelial cell

-lines the surfaces of organs


-very thin to allow diffusion of materials
Transport in cells
Diffusion
The movement of particles from a region of high concentration to a region of lower
concentration until all the particles are evenly distributed.

The rate of diffusion depends on:


1.Concentration-the higher the conc. The faster the rate of diffusion
2.Temperature-the higher the temp,the faster the rate of discussion
3.Size of molecules-the smaller the size,the faster the rate of diffusion

Osmosis
The movement of water molecules from a region of high concentration to a region of
lower concentration through a semipermeable membrane.

Osmosis in plants:

*Plasmolysis occurs when a cell is placed in a concentrated solution.The water


moves from the cell to the outside which results in the shrinkage of the cytoplasm.

*A cell becomes flaccid when it is placed in a concentrated solution.Water from


inside the cell moves out causing the cell to become loose and floppy.
*A cell becomes turgid when it is placed in a dilute solution.Water moves into the cell
causing it to become swollen.

Active Transport
The movement of ions against a concentration gradient(low to high) using
energy(atp).

You might also like