2.1.1 Cell Structure BM

Question 1

What is microscopy

Answer 1

A way of viewing something too small to be seen with the naked eye

Question 2

What are the different lenses and their magnification

Answer 2

Ocular lens (was called eye piece lens) → x10
Objective lens → x4, x10, x40
Oil immersion lens → 5100

Question 3

What is magnification

Answer 3

The degree to which the size or an image is larger than the viewed object itself

Question 4

What is resolution

Answer 4

Resolution is the degree to which it is possible to distinguish between two objects that are very close together
Resolution depends on the wavelength of radiation used in observing the object - the limit of resolution is approximately half the wavelength of radiation used
Election microscopes have a higher resolution than light microscopes due to the short wavelength of the radiation (electron beam) used to form the images

Question 5

How do you convert between millimeters and micrometers

Answer 5

X 1000

Question 6

How do you convert between micrometers und nano meters

Answer 6

x1000

Question 7

What is the formula for image size

Answer 7

Actual (object) size X magnification

Question 8

What is a stage micrometer

Answer 8

The stage micrometer is used to calibrale the eye piece graticule. A stage micrometer consists of a microscope slide on which is engraved a fine and accurate scale.

Question 9

What is an eyepiece graticule

Answer 9

eye piecegraticule is a glass disc fitted into the eyepiece of the microscope. It is marked with a scale from 0 - 10. It will be calibraled to the stage micrometer. It allows you to measure organelles on any magnification.

Question 10

What is a prokaryote

Answer 10

Any cellular organism that has no nuclear membrane,no organelles in the cytoplasm except ribosomes, and has its genetic material in the form of single continuous strands forming coils or loops, characteristic of all organisms in kingdom monera, as the bacteria and blue- green algae

Question 11

What is a eukaryote

Answer 11

Any organism having a fundamental structural unit as a cell type, that contains specialised organisms in the cytoplasm, a membrane bound nucleus enclosing genetic material organised into chromosomes, and an elaborate system of division by mitosis of meiosis, characteristic of all life forms except bacteria, blue green algae and other primitive microorganisms

Question 12

Nucleolus - function

Answer 12

Production of ribosomes
An area within the nucleus responsible for producing ribosomes. Composed of proteins and RNA. RNA is combined
With proteins to form the ribosomes necessary for protein synthesis

Question 13

Mitochondria-function

Answer 13

Production of ATP
Site or final stages of cellular respiration, where the energy stored in bonds is made available for the cell to use by the production of ATP. The more mitochondria the more active the cell

Question 14

Lysosomes - function

Answer 14

Destruction of obsolete organelles
Responsible for breaking down waste material in cells. Play an important role in the immune system as they break down pathogens

Question 15

Centrioles - function

Answer 15

Spindle formation
A component of the cytoskeleton - composed of microtabules. Two associated controls form the centrosome which is involved in organisation of spindle fibres during cell division

Question 16

Ribosomes - function

Answer 16

Protein synthesis
Not surrounded by a membrane. Constructed of RNA molecules made in the nucleolus. Site of protein synthesis

Question 17

Ribosomes - function

Answer 17

Protein synthesis
Not surrounded by a membrane. Constructed of RNA molecules made in the nucleolus. Site of protein synthesis

Question 18

Chloroplasts - function

Answer 18

Light absorption for photosynthesis
Responsible for photosynthesis in plant cells. Found in green parts of plants. Double membrane structure similar to mitochondria. Has fluid enclosed inside called the stroma. Have an internal network or membranes. Contain DNA and ribosomes so can make their own proteins

Question 19

Cytoplasm-function

Answer 19

Cellular reactions
Composed of cytosol (water, salts and organic molecules)
Where cellular reactions are contained

Question 20

Microtubules

Answer 20

Part of the cytoskeleton
Form tubes that determine the shape of the cell
Act as tracks for the movement of organelles around the cell

Question 21

Microfilaments - function

Answer 21

Part of the cytoskeleton
Contractile fibres formed from protein.
Responsible for cell movement and cell contraction

Question 22

Golgi - function

Answer 22

Modification and packaging of proteins

Question 23

Smooth endoplasmic reticulum - function

Answer 23

Lipid and cholesterol synthesis
Responsible for lipid und carbohydrate synthesis and storage

Question 24

Rough end plasma reticulum - function

Answer 24

Contain ribosomes for protein synthesis and movement to Golgi
Responsible for synthesis and transport of proteins

Question 25

The cytoskeleton

Answer 25

a series of intercellular proleins that help a cell with shape, support and movement (transport within cells and cell movement) has main structural components
- microfilaments
- microtubules

Question 26

Light microscope advantages and limitations

Answer 26

advantages →
- easy to use
- cheap (under 11k) to purchase
- true colour but sometimes require staining
- can use live specimen
limitations →
- low resolution due to wavelength of light (0.2 um)
- low magnification (max. 1250x)
- Specimens are thin so may not be representative
election microscopes - scanning (SEM)

Question 27

Scanning electron microscope advantages and limitations

Answer 27

advantages →
- much higher resolution (1nm)
- provides detailed images of surface structures
- high magnification (200000x)
- 3D image

limitations →
- expensive
- extensive training required
- samples must be dead
- black and while or false colour

Question 28

Transmission electron microscope advantages and limitations

Answer 28

advantages →
- much higher resolution (1nm)
- provide detailed images a interior structures
- high magniication ( 500000 x)
limitations →
- expensive
- extensive training required
- samples must be dead
- black and white /false colour
- 2D images

Question 29

Laser scanning confocal microscope advantages and limitations

Answer 29

advantages →
- Objects can be seen at difterent depths
- 3D image is generated
limitations →
- still a light microscope so resolution is similar to the light microscope