LO: To describe the appearance and function of the main organelles found

within cells

Starter

Complete worksheet ‘Well - what do you know?’

BATS

•Describe outline of course and expectations of teachers

•Name organelles in eukaryotic and prokaryotic cells

• Identify similarities and differences between eukaryotic and prokaryotic cells

•Describe the functions of the organelles in eukaryotic and prokaryotic cells

1. Holiday pack - collect in

2. Handbook - go through key points

3. Expectations

4. Independent study

5. Revision Guides

6. Science Blog - Mrs Skuse’s AS Keynotes 2012-13

Introduction to course

You will discover that things are a lot more complicated and

detailed than you thought at GCSE

THIS becomes THIS!

You Tube clips to watch

http://www.youtube.com/watch?v=wJyUtbn0O5Y - the inner life of a cell ( 3 mins)

http://www.youtube.com/watch?v=ky8Xs3JhRc0 - Exploring the living cell - (3 mins)

http://www.youtube.com/watch?v=Ao9cVhwPg84&feature=related - voyage inside the cell (15 mins)

http://www.youtube.com/watch?v=1Z9pqST72is - good lecture about the cell (14 mins)

There are 2 main types of cells - (NOT animal and plant as you learnt at GCSE)

Prokaryotic - these are the oldest types of cells and mainly consist of bacteria -

they do NOT have any membrane-bound

organellesEukaryotic - these evolved more recently and

consist of all plant and animal cells - they contain

membrane bound organelles

Prokaryotic and Eukaryotic

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The bacteriumBacterial

chromosome

Plasmids

Ribosomes

Cell wall

Cell membranes

Cytoplasm

Today we are going to focus on

Eukaryotic cells

Cells are very small and we need microscopes to study themTo see the structures

within a cell we need to use a special kind of microscope called

and ‘electron microscope’ - we will learn more about this

next weekThe detail within a cell is called its

‘ultrastructure’

Structure of an epithelial cell

An epithelial cell is a

eukaryotic cell

Epithelium is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. Epithelial tissues line the cavities and surfaces of structures throughout the body, and also form many glands.

Put the following in order of size starting with the smallest

organ, cell, atom, system, organism, organelle, tissue

An organelle is a specialised subunit within a cell that has a specific function, and is usually separately enclosed within

its own lipid bilayer.

You have been given 2 diagrams of eukaryotic cells

They contain organelles that are visible with an electron microscope.

Using textbooks

label as many as you can

What do cells have organelles? A cell does a huge number of complex things. It is basically a factory. Why does your house need rooms?

The cell does different things in different organelles. It is very similar to your body doing different things with different organs (e.g. your lungs breathe). In a cell mitochondria produce energy, ribosomes make protein. ...

Organelles make cells more efficient

All the molecules, enzymes etc

needed for each purpose can be

found close together in each

organellee.g. all the reactants and

enzymes needed for photosynthesis can be found in a

chloroplast

You need to know the function of the main organelles

Worksheet Cell Ultrastructure

http://www.uni-mainz.de/FB/Medizin/Anatomie/workshop/EM/EMZelleE.html

Electron micrographs

http://www.youtube.com/watch?v=o1GQyciJaTA&feature=related - 6 min clip

Write down everything you know about the nucleus

The nucleus

- Contains the cells hereditary material

- Controls the cells activities 10-20 micrometers

Nucleus - main parts

1. Nuclear envelope - double membrane. It’s outer membrane

is continuous with the endoplasmic reticulum and often

has ribosomes on its surface.

It controls the entry and exit of materials and contains the

reactions happening within it.

2. Nuclear pores - allows the passage of large molecules e.g. mRNA. About 3000 pores in each nucleus - each 40-100nm in diameter.

Nucleus - main parts3. Nucleoplasm - the

granular, jelly-like material that makes up bulk of the

nucleus4. Chromatin - the DNA

found within the nucleoplasm - it makes up chromosomes. When the

cell is not dividing chromosomes are not

tightly coiled but are in a relaxed looser form known

as chromatin5. Nucleolus - manufactures ribosomal RNA and assembles the ribosomes

Nucleus - FUNCTIONS1. Control centre -

of the cell . It produces mRNA and

hence protein.2. Retains the

genetic material - in the form of DNA or

chromosomes

3. Manufactures ribosomal RNA and

ribosomes

The mitochondrion

1. Rod shaped 1-10 micrometers in

length 2. Double

membrane - the outer one controls entry and exit of

material.

The inner membrane is folded to form

cristae.

The mitochondrion3.Cristae -

extensions of inner membrane. They provide a large surface area for attachment of

enzymes involved in respiration3. Matrix - rest of mitochondria. semi-rigid

material containing protein, lipids and traces of DNA which allows the mitochondria to control production of their own proteins.

Enzymes involved in respiration are found in the matrix.

The mitochondrion - functionSome stages of RESPIRATION happen in the mitochondria.

They produce the energy-carrier molecule ATP

Q. - why do muscle cells and epithelial cells have more mitochondria than say a skin cell?

The Endoplasmic reticulum (ER)Elaborate, 3-

dimensional system of sheet-like membranes

that spread throughout the cytoplasm - it is

continuous with the outer nuclear membrane.The membranes

enclose flattened sacs called cisternae

2 types of ER

Rough Endoplasmic reticulum (RER)

Has ribosomes on the outer surfaces

of membranes.

Functions

1. To provide a large surface area for the synthesis of proteins and glycoproteins

2. To provide a pathway for the transport of materials, especially proteins throughout the cell.

Smooth Endoplasmic reticulum (SER)

Lacks ribosomes on its surface and is

often tubular.

Functions

1. To synthesise, store and transport lipids

2. To synthesise, store and transport carbohydrates

Golgi Apparatus

Similar to SER but more compact.

It consists of a stack of membranes that make up

flattened sacs or cisternae, with small

rounded hollow structures called vesicles.

The proteins and lipids produced by the ER are

passed through the Golgi apparatus in strict

sequence.

Golgi Apparatus

The Golgi modifies the proteins

It adds non-protein components e.g.

carbohydrate to them.

It also labels them which allows them to be

accurately sorted and sent to their correct

destinations

Golgi Apparatus

Once sorted the modified proteins and lipids are

transported in vesicles which are pinched off

from the ends of the Golgi cisternae.These vesicles move to

the cell surface where they fuse with the

membrane and release their

contents to the outside

Golgi Apparatus - FUNCTIONS1. Add carbohydrate to

proteins to form glycoproteins

2. Produce secretory enzymes

3. Secrete carbohydrates, such as those used in making

cell walls in plants

4. Transport, modify and store lipids

5. Form lysosomesQ. What kinds of cells will have very well-developed Golgi apparatus?

LysosomesThese are formed when the vesicles produced by the Golgi apparatus contain enzymes such

as proteases and lipases.

Q. Why are these enzymes isolated in lysosomes?

Up to 50 different enzymes in each

lysosomeUp to 1.0 micrometers

in diameter

Lysosomes - FUNCTIONS1. Break down material ingested by phagocytic cells,

such as white blood cells

2. Release enzymes to the outside of the cell

(exocytosis) in order to destroy material around the

cell

3. Digest worn out organelles so that the useful chemicals they are made of can be re-

used

Completely break down cells after they have died

(autolysis)

Q. Name 2 types of cells you might

find a lot of lysosomes in

RibosomesSmall granules found in all

cells either in the cytoplasm or associated

with the RER.

2 Types80S type - found in

eukaryotic cells - 25 nm in diameter

70S type - found in prokaryotic cells -

slightly smaller

Ribosomes - 2 subunits

Each subunit contains ribosomal RNA and

proteinThey occur in vast

numbers - make up to 25% of the dry mass of a

cell.

VERY important in protein

synthesis

Microvilli

Finger-like projections of the epithelial cell.

What do you think their main purpose

is?

To increase the surface area to

allow more efficient absorption

Now do the following

Answer Summary questions on Page 49 of

text book

References Glenn Toole, Susan Toole (2008). A2 Biology. Cheltenham: Nelson

You Tube clips to watch

http://www.youtube.com/watch?v=wJyUtbn0O5Y - the inner life of a cell ( 3 mins)

http://www.youtube.com/watch?v=ky8Xs3JhRc0 - Exploring the living cell - (3 mins)

http://www.youtube.com/watch?v=Ao9cVhwPg84&feature=related - voyage inside the cell (15 mins)

http://www.youtube.com/watch?v=1Z9pqST72is - good lecture about the cell (14 mins)