Mod 2 Chap 2: Cell Structure and Microscopy Flashcards Preview

BIOLOGY AS > Mod 2 Chap 2: Cell Structure and Microscopy > Flashcards

Flashcards in Mod 2 Chap 2: Cell Structure and Microscopy Deck (37)
Loading flashcards...
1

How do you convert from mm to micrometers?

X 1000

2

How do you convert from micrometers to mm?

divide by 1000

3

How do you convert from micrometers to nm?

X 1000

4

How do you convert from nm to micrometers?

Divide by 1000

5

What does epu stand for?

Eye piece units across

6

What is the equation needed for magnification calculations?

I
AM

I = image size
A = actual size
M = magnification

So I = A x M
A = I / M
M = I / A

7

Answer these questions for a light/ optical microscope:
Source of image:
How the beam is focused:
Max effective magnification:
Max resolution:
Can a live specimen be used:
Section / external view:
Cost:
Staining of specimen required:

Source of image: BEAM OF LIGHT
How the beam is focused: LENSES
Max effective magnification: X 1500
Max resolution: 200 nm
Can a live specimen be used: YES
Section / external view: SECTION
Cost: CHEAP
Staining of specimen required: NO

8

Answer these questions for transmission electron microscope (TEM):
Source of image:
How the beam is focused:
Max effective magnification:
Max resolution:
Can a live specimen be used:
Section / external view:
Cost:
Staining of specimen required:

Source of image: ELECTRON BEAM
How the beam is focused: ELECTROMAGNETS
Max effective magnification: X 500,000
Max resolution: 0.2nm
Can a live specimen be used: NO
Section / external view: SECTION
Cost: EXPENSIVE
Staining of specimen required: YES WITH METAL SALTS

9

Answer these questions for a scanning electron microscope (SEM):
Source of image:
How the beam is focused:
Max effective magnification:
Max resolution:
Can a live specimen be used:
Section / external view:
Cost:
Staining of specimen required:

Source of image: ELECTRON BEAM
How the beam is focused: ELECTROMAGNETS
Max effective magnification: X 100,000
Max resolution: 10 nm
Can a live specimen be used: NO
Section / external view: EXTERNAL
Cost: EXPENSIVE
Staining of specimen required: COATED WITH GOLD

10

List the four types of microscope

Scanning Electron Microscope
Light / Optical
Transmission Electron Microscope
Laser

11

Define Magnification:

How many times larger the image is than the actual size of the object being viewed.

12

Define Resolution:

The ability to see individual objects as separate entities.

13

Which types of microscope can produce 3D images?

Scanning (SEM)

14

Which microscope uses fluorescent dyes to stain specimens?

Laser scanning

15

What are the organelles present in animal cells?

Plasma membrane
Nucleus
Nucleolus
Nuclear envelope
Nuclear pore
Peroxisome
Ribosome
Golgi complex
Lysosomes
Secretory vesicle
Mitochondrion
Cytoplasm
Centrioles
Cytoskeleton - filaments
Microtubules
Smooth endoplasmic reticulum
Rough endoplasmic reticulum

16

What are the organelles present in plant cells?

Plasma membrane
Cytoplasm
Mitochondria
Cytoskeleton: micro tubules, filaments
Nucleus
Nucleolus
Nuclear envelope
Nuclear pore
Rough endoplasmic reticulum
Smooth endoplasmic reticulum
Golgi complex
Peroxisome
Cell wall
Chloroplast
Permanent vacuole: tonoplast
Plasmo desmata
Ribosomes

17

What is the function of the centrioles?

Component of the cytoskeleton involved in assembly and organization of spindle fibers during cell division

18

Describe the preparation and examination of slides used in light microscopy.

- sample placed on a slide + allowed to air dry
- then heat fixed by passing through a flame
- specimen then adheres to microscope slide + takes up stains

19

Describe the various methods in which samples and specimens can be prepared for examination by light microscopy.

- dry mount: specimen place onto slide dry + covered with a slip
- wet mount: specimens suspended in liquid such as water + covered with a slip
- squash slides: wet mount is prepared, cover slip is pressed down with a lens tissue, damage to cover slip can be avoided using two microscope / squash slides
- smear slides: edge of a slide used to smear sample on another slide, cover slip then placed on top.

20

Describe the importance of the cytoskeleton in terms of its structure.

- it's a network of protein structures within cytoplasm

CONSISTS OF:
- rod like MICROFILAMENTS made of subunits of protein actin, they are polymers of actin.
- INTERMEDIATE FILAMENTS about 10nm in diameter
- MICROTUBULES that are straight and cylindrical, made of subunits of protein tubulin
- CYTOSKELTAL MOTOR PROTEINS: myosins, kinesins, and dyenins are molecular motors, they are enzymes that allow hydrolysis of ATP as the energy source.

- cytoskeleton is present in all eukaryotic cells
-network of fibers necessary for shape and stability of cell
- holds organelles in place
-controls cell movement and movement of organelles within cells

21

Describe the importance of the cytoskeleton in terms of cell movement.

- movement of cells like phagocytes depends on activity of actin filaments in cytoskeleton
- filament lengths change w/ addition + removal of monomer subunits. (Rate these subunits added is diff at each end of filament)
- so at certain concentrations, subunits added at one end + removed at other, called 'treadmilling', causing cells to move in a particular direction.

22

Describe the differences in structure and ultra structure of prokaryotic and eukaryotic cells.

Eukaryotic Prokaryotic

-Has membrane bound organelles. -Does not
-Has a nucleus. -Does not
-Large ribosomes. -Small ribosomes
-DNA on linear chromosomes. -DNA on circular
chromosomes
-DNA within cytoplasm. -DNA within nucleus
-ATP production in folded regions of. -ATP production in
cell membrane called mesosomes. mitochondria
-cellulose based cell wall. -peptidoglycan based
cell wall
- may have undulipodia. - may have flagella
(Cilia and flagella)

23

What is differential staining?

It can distinguish between two types of organisms that would otherwise be difficult to differentiate between different organelles of a single organism within a tissue sample.

24

What techniques can be used when staining samples in microscopy?

Gram Stain Technique - separates bacteria into two groups

Acid-fast technique - differentiates species of Mycobacterium from other bacteria.

25

What is the function of ribosomes?

- constructed of RNA molecules made in nucleolus
- site of protein synthesis

26

What is the function of chloroplasts?

- responsible for photosynthesis in plant cells
- have internal network of membranes forming flattened sacs called thylakoids, several thylakoids stacked together = granum (plural grana)
- grana contain chlorophyll pigments, where light dependant reactions occur in photosynthesis.
- contain DNA + ribosomes so can make own proteins

27

What is the function of cilia?

- stationary cilia present on surface of many cells, have important functions in sense organs e.g. nose.
- mobile cilia beat rhythmically to create current + move fluids or objects away from cell

- cilia = hair like
- flagella = whip like

28

What is the function of the Golgi apparatus?

- role in modifying proteins + packaging them into vesicles, (secretory vesicles if proteins are destined to leave cell /lysosomes, which stay in cell).

29

What is the function of the rough endoplasmic reticulum? Describe it.

- has ribosomes bound to surface + is responsible for synthesis + transport of proteins

- is network of membranes enclosing flattened sacs called cisternae
- connected to outer membrane of nucleus

30

What is the function of the smooth endoplasmic reticulum? Describe it.

- responsible for lipids and carbohydrate synthesis and storage

- a network of membranes enclosing flattened sacs called cisternae
- connected to outer membrane of nucleus