organisation cells and microscopy- 01

magnification

conversion values for cm, mm, nm,µm

organelle

cells

definitions

formula

actual size- size of object in real life

magnification= how much the image has been zoomed

image size- size of image

image size= actual size x magnifcation

magnification= image size / actual size

actual size= image size / magnification

prokaryotes

eukaryotes

DNA in nucleas

simple structure

plant cells and animal cells

no membrane bound organelles

naked DNA

membrane bound organelles

no seperate organelles e.g. nucleas

cell membrane

cell wall

cytoplasm

mitochondira

nucleus

vacuole

ribsome

chloroplast

very small organelles

structure not seen under light microscope

perform protein synthesis

apperence: solid on light microscope

function to synthesize proteins

function is to contain DNA- controls cell activities including cell division

appearance: jelly like fluid

function is that it is the site of many reactions e.g. protein synthesis

appearance: thin layer of lipid molecules

function: controls what can enter/ leave the cell- partially permeable

small oval/ rounded organelles

double membrane

site of respiration

energy release from glucose

very strong

function: supports the shape of cell

appearance: fibrous layer made from cellulose

store of cell sap in plants

appearance:Vacuoles have a simple structure: they are surrounded by a thin membrane and filled with fluid and any molecules they take in

function: site of photosynthesis

appearance: small rounded organelles- contains chlorophyll

10 mm = 1 cm

1,000 mm = 1m

1,000 µm = 1 mm

100 cm = 1 m

100 nm = 1 µm

required practical 1

Use a dropping pipette to put one drop of water onto a microscope slide.

Use the mounted needle and forceps to peel off a thin layer of epidermal tissue from the inner surface of the onion.

There may be some liquid around the edge of the coverslip. Use a piece of blue roll to soak this liquid up.

Use forceps to put this thin layer onto the drop of water that you have placed on the microscope slide.

Put the slide on the microscope stage. Draw a large, labelled diagram of one cell, viewed under high power. Record the magnification next to your drawing.

Make sure that the layer of onion cells is flat on the slide.

Put two drops of iodine solution onto the onion tissue.

Carefully lower a coverslip onto the slide. Do this by: placing one edge of the coverslip onto the slide
using the forceps or mounted needle to lower the other edge onto the slide