1.1 Introduction to cells

Question 1

Cell Theory

Answer 1

1. living organisms are composed of cells
2. cells = smallest unit of life
3. cells come from pre-existing cells

Question 2

Cell Commonalities

Answer 2

• each cell is surrounded by membrane
• genetic material stores instructions for cell activities
• chemical reactions catalysed by enzymes
• own energy release system that powers its activities

Question 3

Exceptions of cell theory

Answer 3

1. muscle tissue - multinucleate, larger than most animal cells
2. fungal hyphae - multinucleate
3. algae - many have 1 microscopic cell

Question 4

Functions of Life

Answer 4

1. nutrition
2. metabolism
3. growth
4. response to stimuli
5. reproduction
6. homeostasis
   7/8. evolution / excretion

Question 5

Paramecium

Answer 5

• unicellular
• nucleus can produce extra nuclei
• food vacuoles have smaller organisms previously consumed by paramecium (digested + absorbed into cytoplasm for energy)
• cell membrane controls what enters / leaves
• contractile vacuoles keep cell water content in tolerable limit
• metabolic reactions in cytoplasm
• cilia moves it through water

Question 6

Chlamydomonas

Answer 6

• unicellular
• green, photosynthesis
• NOT a plant, cell wall not made of cellulose
• nucleus can divide

Question 7

1 mm = ? μm

Answer 7

1 mm = 1,000 μm

Question 8

1 μm = ? nm

Answer 8

1 μm = 1,000 nm

Question 9

1 cm = ? μm

Answer 9

1 cm = 10,000 μm

Question 10

Viruses

Answer 10

• not made of cells (can’t metabolise)
• parasite
• has nucleic acid + covered in protein coat
• recognises cell surface, attaches, injects nucleic acid, takes over cell

Question 11

Resolution

Answer 11

Ability to distinguish 2 objects as separate entities

Question 12

Magnification

Answer 12

Ability to increase size of viewed objects

Question 13

Magnification formula

Answer 13

image size (length of scale bar) / actual size (value of scale bar)

Question 14

COLOUR in Light VS Electron Microscope

Answer 14

Light - shows colour

Electron - black and white

Question 15

MAGNIFICATION in Light VS Electron Microscope

Answer 15

Light - lower mag

Electron - higher mag

Question 16

SPECIMENS in Light VS Electron Microscope

Answer 16

Light - living specimens

Electron - non living specimens

Question 17

RESOLUTION in Light VS Electron Microscope

Answer 17

Light - lower resolution

Electron - non living specimens

Question 18

FIELD OF VIEW in Light VS Electron Microscope

Answer 18

Light - smaller f.o.v.

Electron - larger f.o.v.

Question 19

PREPARATION in Light VS Electron Microscope

Answer 19

Light - easy sample prep

Electron - complex sample prep

Question 20

ACCESS in Light VS Electron Microscope

Answer 20

Light - easy access, cheaper

Electron - expensive, difficult to access