Cell structure Flashcards
Protoplasm
all the living parts of a cell
Ultrastructure
is the detail of a structure as seen using an electron microscope
Objective lens
Low power
Medium power
High power
Light microscope parts
Objective lens
Clips
Light
Eye piece lens
Stage
Coarse focus
Fine focus
Experiment using a light microscope : To examine a plant cell
Sample of onion cells
Stain with iodine - to see cell wall and nucleus
Apply coverslip at 45° angle to avoid air bubbles
Organelles
Cells contain a variety of internal structures called organelles.
An organelle is a component that preforms specific functions for the cell (eg:) mitochondria-> respiration
Light microscope magnifys..
1000 times
Electron microscope magnifies
250,000 times
SEM
Scanning electron microscope
(Surface)
TEM
transmission electron microscope (Internal)
Chlorophyll
Green pigment
Function of the cell membrane
- Retain cell contents
- Controls what enters and leaves the cell (allows water and oxygen to pass freely however sodium ions and large proteins have to be moved across using energy)
- Gives some support
- Semi permeable
What is the cell membrane made of?
- Phospholipid bilayer (structural lipid)
- Proteins
Ultrastructure of the nucleus
The nucleus is the control centre of the cell (contains DNA, RNA)
The nucleus is surrounded by a double membrane with nucleur pores
Allows controlled entry and exit of molecules into and out of the nucleus
DNA
Deixyribonucleic Acid
Chromatin
Chromosomes intertwine to from chromatin when the cell is not divided
Nucleolus
Location: nucleus
Function: makes ribosomes
Function of ribosomes
Makes protein
Mitochondria Function
- Supply energy to the cell (known as the powerhouse)
- Site of respiration in the cell (release of energy from food
Cells with lots of mitochondria include:
Animals: muscle and liver
Plant: meristem (growing tips of roots and shoots)
Inactive mitochondria includes
Outer membrane
Inner membrane
Infolding (Christae) (not a lot)
Loop of DNA
Active mitochondria includes
Outer membrane
Inner membrane
Infolding (christae) ( a lot)
Loop of DNA
Function of Christae
Increases the surface are for respiration therefore more energy is released.
Chloroplast: Function
Photosynthesis
Contains chlorophyll (green pigment)
Magnesium - needed for chlorophyll
Cell wall function
Cell walls - cellulose - support and strength
They’re fully permeable
Prokaryotic cell
- Don’t have a nucleus or membrane enclosed organelles
- Are small/ microscopic
(Eg:) bacteria 🦠
Eukaryotic cell
- Do have a nucleus and membrane enclosed organelles
- Bigger than bacterial cell
(Eg:) plant and animal cells 🌱
Where is DNA found?
Chromosomes or chromatin in the nucleus
Vacuole function
To strengthen the cell and storage
Experiment using a light microscope : Animal cell
Sample of cheek cells
Stain using methylene blue
45° angle apply coverslip
Animal cell: Ultrastructure contents
Cell membrane
Nuclear membrane
Nucleus (nucleolus, nuclear membrane, nuclear pores, chromatin)
Ribosome
Cytoplasm
Mitochondria
Plant cell: Ultrastructure contents
Cell membrane
Cell wall
Vacuole
Nucleus (nucleolus, nuclear membrane, nuclear pores, chromatin)
Cytoplasm
Mitochondria
Chloroplast