Cell Structure and Microscopy

Question 1

What Structures are in a Eukaryotic Cell?

Answer 1

Cytoplasm, Nucleus, Ribosomes, Mitochondria, Plasma Membrane, Nucleolus, R.E.R, S.E.R, Golgi Apparatus, Lysosomes, Vacuole**

Question 2

What Structures are only in Plant Cells?

Answer 2

Chloroplasts, Permanent Vacuole, Cell Wall (Cellulose)

Question 3

What Organelle can you only find in an Animal Cell?

Answer 3

Centriole

Question 4

What are the Structures of a Prokaryotic Cell?

Answer 4

Cytoplasm, Ribosomes, Plasma Membrane, Chloroplasts, Vacuole, Cell wall (Peptidoglycan), Nucleoid (DNA), Plasmids, Slime Capsule, Pili, Flagella

Question 5

What are the cell sizes of a Prokaryotic and Eukaryotic?

Answer 5

Prokaryotic: 0.5-5um
Eukaryotic: 10-100um

Question 6

What are the Ribosome’s realtive sizes?

Answer 6

Prokaryotes: 70S (approx 10-20nm)
Eukaryotes: 80S (approx 22nm)

Question 7

What is the process of producing ATP in the Mitochondria called?

Answer 7

Oxidative Phosphorylation

Question 8

What are the 4 different types of Slide called?

Answer 8

Dry Mount
Wet Mount
Smear Slide
Squash Slide

Question 9

How is a Wet Mount prepared?

Answer 9

1. Specimens are suspended in a liquid e.g. water or immersion oil.
2. A cover slip is placed at an angle
   Aquatic organisms and other living examples can be viewed.

Question 10

What are the 4 Steps of preparing a slide and what happens at each step?

Answer 10

o Fixing- Chemicals used to preserve specimens in as near natural state as possible.
o Sectioning- Specimens dehydrated with alcohol then placed in a mold with wax to be cut with a knife (microtome)
o Staining- Treated with colors to see structures of a cell.
o Mounting- Specimens secured to slide and cover slip is used.

Question 11

Definition of Magnification?

Answer 11

how much bigger the image is compared to the original object viewed with the naked eye

Question 12

Definition of Resolution?

Answer 12

The ability to distinguish between two points on an image.

Question 13

Features of a Compound Light Microscope

Answer 13

o Uses visible light to illuminate a thin section of a living sample
o Low resolution compared to electron
o Can see thin cross section of a living thing (slice)

Question 14

Features of a Confocal Laser Scanning Microscope

Answer 14

o Can see thin slices of an intact sample - cell structures
o Low resolution compared to SEM
o Only see fluorescent objects and can cause artefacts
o Can see mitosis/movement of mitochondria

Question 15

Advantages of Electron Microscopy

Answer 15

o Done with a beam of electrons with a wavelength of less than 1nm
o Gives higher detail of the cell ultrastructure
o Produces images of up to x500,000 magnification

Question 16

Disadvantages of Electron Microscopy

Answer 16

o Very expensive to use and restore
o Have to be used in a controlled environment
o Specimens can be damaged due to the complex process
o Specimens must be dead
o Can be a problem with artefacts

Question 17

Features of a Scanning Electron Microscope (SEM)

Answer 17

o Can see the surface of objects at high resolution
o Resolution not as high as TEM
o Specimens must be dead
o Generated 3D image that can be colored
o Lower limit of resolution than TEM
o Magnification up to x100,000

Question 18

Features of a Transmission Electron Microscope (TEM)

Answer 18

o A beam of electrons are transmitted through a specimen
o Resolving power of 0.5nm
o Can see thin cross section of an object
o Specimens must be dead
o Very high resolution - higher than SEM
o Magnification up to x500,000

Question 19

How do prokaryotes reproduce?

Answer 19

Binary Fission

Question 20

What 3 structures make up the Cytoskeleton?

Answer 20

Microtubles, Microfilaments, Intermediate Filaments

Question 21

Roles of the Microtubles

Answer 21

o Globular tubulin proteins
o Form hollow tubes to form as scaffold
o Determine cell shape
o Act as pathways for vesicles and organelles

Question 22

Roles of Microfilaments

Answer 22

o Composed of actin (protein)
o Provide contractile motion when they collide with myosin
o Involved with contraction during cytokinesis
o Support the cell
o Responsible for cell movement

Question 23

Roles of Intermediate Filaments

Answer 23

o Entwined dimers of proteins
o Add mechanical strength
o Help maintain cell integrity

Question 24

Overall role of the cytoskeleton

Answer 24

o Provide strength and support
o Determine cell shape
o Movement of organelles
o Hold organelles in place
o Make up centrioles and spindle fibers

Question 25

Process of Protein Production

Answer 25

o DNA is copied (transcription), mRNA moves out of the nucleus to the ribosomes
o The ribosomes coordinate the assembly of proteins (translation) using the mRNA
o The mRNA is translated and the proteins enter the cis face of the Golgi body in a vesicle
o The proteins are processed and modified and packaged up to leave in a vesicle from the trans face
o The vesicles fuse to the plasma membrane and the proteins are released (exocytosis)

Question 26

Features of Nucleolus

Answer 26

o Lives in Nucleus
o Not membrane bound
Produces rRNA and communicates by sending mRNA to the ribosom

Question 27

Features of Rough Endoplasmic Reticulum

Answer 27

o Flattened membrane to transport and synthesize proteins
o Made rough due to ribosomes
o Packages proteins

Question 28

Features of Nucleus

Answer 28

o Surrounded by nuclear envelope (double membrane)
o Contains nucleolus
o Stores DNA as chromatin and coordinates cells activities such as growth, protein synthesis and reproduction.