cells as the basis of life

biocanvas.net

Cells as the basis of lifeSarah Jones

All LIVING things are made of CELLS.

Fibroblasts are cells that help maintain tissue structure by secreting proteins like collagen and elastin - biocanvas.net

The Discovery of Cells

In the seventeenth century, Robert Hooke looked

at thin slices of cork under a microscope that he

had made from lenses. He observed small box-like

shapes inside the cork. He called the little boxes

that he saw cells.

marshscience7.blogspot.com

http://discovermagazine.com/2015/june/21-leeuwenhoeks-lucky-break

Electron Microscopy Images Of Coffee

coffeeguru4iphone.wordpress.com

boneresearchsociety.org

SEM Image of Trabecular bone

Unicellular organisms – single-celled

organisms.

Multicellular organisms – have specialised

cells that carry out specific functions.

Unicellular Algae – biocanvas.net

Carry out all of the functions of life

M ovement

R espiration

S ensitivity

G rowth

R eproduction

E xcretion

N utrition

Unicellular Organisms

Diatom – biocanvas.net

Under the five kingdom system cells can be

divided into two basic types.

Prokaryotic cells - simple cells without distinct

membrane bound organelles or nucleus.

Eukaryotic cells - more complex with

membrane bound organelles and nucleus.

Animal Cell

• Exist as part of a multicellular organism.

• Specialisation of cells into many types (cell

differentiation).

• Possess nucleus and membrane bound

organelles.

Plant Cell

en.wikipedia.org

• Exist as part of a multicellular organism.

• Specialisation of cells into many types (cell

differentiation).

• Possess nucleus and membrane bound

organelles.

Plant vs Animal

Plant and animal cells have many similarities

because they are both eukaryotic.

They also have some differences:

Plasma Membrane

• The surface of exchange for materials

between the inside and outside of the cell.

• IN – oxygen, nutrients and water

• OUT – carbon dioxide, waste and products

such as proteins

http://www.histology.leeds.ac.uk/cell/plasma_membrane.php

Plasma Membrane Function

1. Hold cell together

2. Control what goes in and out – diffusion,

osmosis, active transport

3. Protect the cell

4. Allow the cell to recognise and be

recognised – cell signaling and immunity

5. Bind to other cells and molecules

6. A sit for biochemical reactions – enzymes,

areas for reactions

en.wikipedia.org

Diffusion

• Larger cells require more resources to be

imported and more products to be exported.

• As cells get larger the SURFACE AREA to

VOLUME RATIO gets smaller.

• Increasing cell size – less efficient

exchange process.

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Brownian Motion – the random movement of

particles in a liquid or gas. Due to Brownian

motion particles will diffuse evenly through the

system over time.

Diffusion is the passive net movement of

molecules from regions of high concentration

to low concentration.

ekgenius.net/

Facilitated diffusion is the passive net

movement of particles from regions of high

concentration to low concentration, through

selectively permeable membrane (plasma

membrane), facilitated by carrier proteins.

ccaoscience.wordpress.com

en.wikipedia.org

Osmosis

Osmosis is the passive net movement of

water molecules from regions of low solute

concentration to high solute concentration,

through partially/selectively permeable

membrane.

bronxguildlivingenvironment.blogspot.com

Osmosis is also movement down a concentration

gradient –we are considering the movement of

water molecules, not the solute molecules.

ekgenius.net/

Active Transport

Active transport uses energy (ATP) to move

molecules against a concentration gradient,

using membrane protein pumps.

www.premedhq.com

en.wikipedia.org

Endocytosis

en.wikipedia.org

Exocytosis

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Parts of a Generalised Animal Cell

https://en.wikipedia.org/wiki/Cell_nucleus

• Contains the chromosomes (genetic

information) for the cell.

• Controls the activities of the cell.

Nucleus

• Double membrane - outer membrane and

inner membrane.

• Inner membrane is folded forming cristae.

• The interior contains an organic matrix

containing chemical compounds.

• Site of aerobic respiration.

Mitochondria

Rough Endoplasmic Reticulum

• A membrane system of flattened parallel

cavities which are interconnected and covered

with ribosomes.

• An intracellular transport system.

Golgi Apparatus• Consists of a stack of flattened cavities which

package substances produced by the cell into

vesicles.

• These vesicles can fuse with the cell

membrane (exocytosis) or become

lysosomes (digestive vesicles).

Plant Cell Walls• The main component of plant cell walls is

cellulose.

• Cellulose molecules are arranged in bundles

called microfibrils.

• The function of the plant cell wall is to provide

strength and support the plant.

Photosynthesis

Chloroplast

biology-themiracleoflife.blogspot.com

mrkubuske.wordpress.com

Cellular Respiration Plants

www.tvdsb.ca

Cellular Respiration Humans

http://mrkubuske.files.wordpress.com

Comparing Cellular Respiration and

Photosynthesis

www.accessexcellence.org

www.bbc.co.uk

Prokaryotic organisms are commonly called

bacteria.

They are cells with a simple structure.

They have no membrane around the nucleus

and lack any membrane bound organelles.

Blue-green bacteria make their own food by

photosynthesis.

en.wikipedia.org

Prokaryotic Cell Parts

• Cell Wall – protective protein-based coating.

• Plasma Membrane – selectively permeable.

• Pili – attach to other bacteria for DNA transfer.

• Cytoplasm – contains enzymes for metabolic

reactions.

• Nucleoid – closed-loop of bacterial DNA.

• Ribosomes – protein synthesis – transcription

and translation.

• Flagella – causes movement.

en.wikipedia.org

Prokaryotic Reproduction – Binary Fission

http://evolution-textbook.org/content/free

Cell Division

• For an organism to grow larger it needs to

produce more cells – and each new cell

needs a copy of the organism’s DNA.

• Tissue Repair

• Asexual Reproduction

commons.wikimedia.org

Mitosis

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