Unit 1 - Key concepts Flashcards
What 2 types of cells are there
Prokaryotic and Eukaryotic
What makes a cell Eukaryotic
If a cell has:
- A cell membrane
- A cytoplasm
- Nucleus containing DNA
Eukaryotic
What makes a cell prokayotic
If a cell has:
- A cell wall
- A cell membrane
- A cytoplasm
- A plasmid of DNA
What is a Nucleus
A nucleus is an organelle which contains DNA, which codes for a particular protein needed to build new cells
What is the nucleic membrane
A membrane that contains the nucleus
What is the cytoplasm
A liquid substance containing enzymes in which chemical reactions occur
What is the cell membrane
A membrane which controls what enters and leaves the cell
What is the mitochondria
Where aerobic respiration reactions occur
What is the ribosomes
Where protein synthesis occurs
What is the chloroplast
Where protein synthesis takes pace, providing food for the plant
What is the vacuole
An organelle which contains cell sap, found within the cytoplasm.
What is the cell wall
An organelle that is made from cellulose and provides strength to the cell
What is the flagella
A long tail attached to bacteria allowing them to move
What is a plasmid
A small ring of chromosomal DNA
What process do cells go through to specialise
Differentiation
What is a stem cell
A cell which can differentiate throughout its life
What is a specialised cell
A cell which has been differentiated
Give 3 examples of specialised cells in animals
- Sperm cells
- Egg cells
- Ciliated epithelial cells
How are sperm cells specialised to be suitable for its purpose
- A streamlined head and long tails to aid swimming
- Many mitochondria to supply a lot of energy
- The acrosome which has digestive enzymes to break down the outer layer of the egg cell
How are egg cells specialised to be suitable for its purpose
- Surrounded by a special cell membrane which can only accept one sperm cell
- A lot of mitochondria to provide an energy source for the developing embryo
- Large size and cytoplasm to allow quick cell division
How are Cilitated Epithelial Cells specialised to be suitable for its purpose
Long hair like processes called cilia waft bacteria trapped by sticky mucus down into stomach acid
Give 3 examples of specialised cells in plants
- Root hair cells
- Phloem cells
How are root hair cells specialised to be suitable for their functions
- Specialised to absorb water through osmosis
- Large surface area to increase water absorption
How are Phloem cells specialised to be suitable for their functions
- Sieve plates, which are formed in cell walls allowing substance movement between cells
- Companion cells, which provide energy to phloem cells
What do microscopes do
Enlarge images of structures like cells
What 2 type of microscopes are there
Light and electron
How do light microscopes work
2 lenses are illuminated from underneath
What is the magnification of a light microscope
~2000x
What is resolving power
The ability of an optical instrument or type of film to separate or distinguish small or closely adjacent images.
What is the resolving power of a light microscope
200nm
Lower ____ ∝ more ____
- RP
- Detail
When was the electron microscope made
1931
How do microscopes work
They use electrons to form an image, which have a much smaller wavelength than light
What are the 2 types of electron microscopes
- Scanning Electron Microscope (SEM)
- Transmission Electron Microscope (TEM)
Give 2 differences between SEM and TEM microscopes
- SEM makes 3D images, and TEM makes 3D images
- SEM’s RP is 10nm, and TEM’s RP is0.2nm
Give 1 similarity between SEM and TEM microscopes
2,000,000x magnification
How to calculate the magnification of a light microscope
M=M(EL)xM(OL)
Where M=magnification
EL=Eyepiece lens
OL=Objective lens
How to calculate the size of an objective
S(O)=S(I)/M
Where S=Size
O=Object
I=Image
M=magnification
Name the 5 parts of a light microscope
- Eyepiece
- Barrel
- Turret
- Lens
- Stage
What is the function of the eyepiece
Used to view specimens
What is the function of a barrel
To focus the image
What is the function of the turret
To change the magnification of the used lens
What is the function of the lens
Increase the magnification of the specimen
What is the function of the stage
The flat surface on which we place the specimen
How to use a light microscope
- Place the slide on the stage and look through the eyepiece lens.
- Turn the focus wheel to obtain a clear image.
- Start with the lowest objective lens magnification.
- Increase the magnification of the objective lens and refocus.
How to prepare a slide
- Take a thin layer of cells from your sample.
- Add a small amount of chemical stain.
- Apply the cells to your glass slide.
- Carefully lower a coverslip onto your slide, avoiding air bubbles.
