3.1

HideShow resource information
  • Created by: Aniqa
  • Created on: 02-01-13 02:37

MICROSCOPES

LIGHT MICROSCOPE:

Advantages:

  • Cheap and easy to use, organism is unharmed

Disadvantages:

  • Limited power/resolution

ELECTRON MICROSCOPE:

Advantages:

  • Huge powers/resolution

Disadvantages:

  • Expensive and particles may collide with organism causing damage
1 of 10

PROKARYOTES

- Lack structure and organisation 

NUCLEOID - Single strand DNA

CYTOPLASM - Enzymes, ribosome, food storage

MESOSOME - Respiration

2 of 10

EUKARYOTES

CONTAIN:

MEMBRANE

Nucleus surrounded by double membrane, contains DNA, RNA and CHROMATINS - Proteins.

MITOCHONDRIA 

Folded inner membrane; CRISTAE. Ribosomes contained in MATRIX.

CENTRIOLES

Cell division; produce spindle fibres.

CYTOSKELETON

Creates 3D structure, keeps organelle in place with MICROFILAMENTS.


3 of 10

...

VACUOLES

Allow control of water content. Membrane made and lost.

SMOOTH ENDOPASMIC RETICULUM (SER)

Control synthesis and transport.

ROUGH ENDOPLASMIC RETICULUM (RER)

Isolate and transport proteins made. Contain ribosome on surface

GOLGI APPARATUS

Vesicles cluster around, CISTERNAE formed. Contain lysosome

LYSOSOME: Contains digestive enzymes. Extracellular. 

- APOPTOSIS occurs if lysosome is damaged; releases enzyme which destroy the cell.

4 of 10

Labelled eukaryote

~~

5 of 10

Cellular organisation

CELLS:

(liver cells)

TISSUES:

One or few types of cells that work together to form a function (muscles)

ORGANS:

Various tissues grouped (heart)

SYSTEMS:

Various organs grouped for a large scale function (digestive system)


6 of 10

MITOSIS

Allows asexual reproduction for exponential growth.

All cells have the same amount of DNA.

No genetic variation.


7 of 10

4 PHASES

PROPHASE:

  • Chromosomes condence
  • Nuclear envelope broken
  • Nucleolus disappears
  • Spindle forms
  • Centrioles move to opposite poles

METAPHASE:

  • Chromatids line up at the equator
  • Attach to spindle fibres 
  • Fibres attach to centriomere

ANAPHASE:

  • Spindle fibres contract
  • Fibres pull chromatids apart with centriomere leading
8 of 10

....

TELOPHASE:

  • Chromosomes condense
  • Nuclear envelope forms
  • Nucleolus reappears
  • Two new nuclei

INTERPHASE:

  • Cytoplasm divides
  • Two new identical daughter cells are formed


9 of 10

ROOT TIP SQUASH

Technique used to observe mitosis:

  • 5mm of a root tip from a plant is cut

This is where mitosis occurs in the root

  • Add stain (DCPIP)

Stain to highlight chromosomes, usually acid to soften the tissues

  • Break open on a slide and squash carefully

Spread out the cells so the layer is only one cell thick for ease of viewing

  • Add more stain and look at the slide under a microscope

Microscope used because cells and chromosomes are small

10 of 10

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all resources »