The origin of cells and cell theory

Question 1

Can protocells self-replicate?

Answer 1

Yes

Question 2

How do protocells replicate?

Answer 2

Nucleotides enter the protocells and are incorporated into the nucleotide chain.

Question 3

What kind of cells were found in 3.5 billion year old rocks rocks in the 1990s?

Answer 3

Cyanobacteria

Question 4

How long did it take for cells to appear after the formation of Earth?

Answer 4

500 million to a billion years.

Question 5

Who first coined the term “cell”?

Answer 5

Robert Hooke in 1665

Question 6

What are the principles of cell theory?

Answer 6

1. Cells are the fundamental units of life.
2. All organisms are composed of cells
3. All cells come from preexisting cells
4. Modern cells evolved from a common ancestor

Question 7

What are the implications of cell theory?

Answer 7

1. Functions of all cells are similar
2. Life is continuous
3. Origin of life was the origin of cells

Question 8

What are the distinctive traits of all living things?

Answer 8

• Take in matter and energy from the environment
• they respond to environmental stimulus
• conduct homeostasis
• they grow and develop
• they reproduce
• they pass genetic information from one generation to the next

Question 9

What happens as cell volume increases?

Answer 9

Chemical activity, need for resources and waste removal increases.

Question 10

What are the two basic types of microscopes?

Answer 10

Light and electron

Question 11

How do electron microscopes work?

Answer 11

Electromagnetics are used to focus an electron beam.

Question 12

Where is DNA located in a prokaryotic cell?

Answer 12

The nucleoside.

Question 13

What encloses prokaryotes?

Answer 13

A cell membrane and a rigid cell wall.

Question 14

What additional structures does a bacterial cell contain?

Answer 14

An additional outer membrane and a polysaccharide layer.

Question 15

What is the function of the internal membranes found in cyanobacteria?

Answer 15

Photosynthesis.

Question 16

What are the extracellular structures found on prokaryotes?

Answer 16

Flagella, pili and fimbriae

Question 17

What is the function of the cytoskeleton?

Answer 17

To maintain cell shapes and play roles in cell movement and cell division.

Question 18

What is cell fractionation?

Answer 18

Separating a cell into its composite parts for study.

Question 19

Are ribosomes organelles?

Answer 19

No

Question 20

What is the nucleoplasm?

Answer 20

All parts of the nucleus bar the nucleolus.

Question 21

Where is the nuclear envelope found?

Answer 21

Around the nucleus.

Question 22

What is included in the endomembrane system?

Answer 22

The nuclear envelope, cell membrane, ER, Golgi apparatus and lysosomes.

Question 23

What are the functions of the RER?

Answer 23

• make membrane bound proteins
• transport proteins around the cell
• site of chemical modification of proteins
• site of the formation of disulphide bridges and tertiary folding
• formation of glycoproteins

Question 24

How do proteins enter the lumen of the RER?

Answer 24

Through pores

Question 25

What is the function of the smooth ER?

Answer 25

- makes toxins polar so they can be removed - site of glycogen degradation - synthesis of lipids and steroids - storage of calcium ions

Question 26

What is the function of the Golgi apparatus?

Answer 26

Process and package proteins received from the RER

Question 27

What is the Golgi apparatus comprised of?

Answer 27

The cisternae and vesicles

Question 28

What are the three regions of the cisternae?

Answer 28

1. the cis region nearest the nucleus 2. the trans region found closest to the membrane 3. the medial region found in between

Question 29

What is the function of lysosomes?

Answer 29

It is where macromolecules are hydrolysed into monomers.

Question 30

Where do primary lysosomes originate from?

Answer 30

The Golgi apparatus

Question 31

How is a secondary lysosome formed?

Answer 31

By the binding of the phagosome to the primary lysosome

Question 32

What happens to the used secondary lysosome?

Answer 32

It fuses with the cell membrane and releases digested particles into the environment (exocytosis).

Question 33

What is a phagosome?

Answer 33

The pocket that absorbs material in phagocytosis.

Question 34

What is autophagy?

Answer 34

Programmed destruction of cells components.

Question 35

What types of cell contain plastids?

Answer 35

Plant and some protist.

Question 36

What is the internal membrane of chloroplasts comprised of?

Answer 36

Thylakoids containing chlorophyll

Question 37

What is the area outside the thylakoid membrane called?

Answer 37

The stroma

Question 38

What is the function of peroxisomes?

Answer 38

Accumulation of peroxides.

Question 39

What is the structure of peroxisomes?

Answer 39

Single membrane and granular interior.

Question 40

Where are glyoxysomes found?

Answer 40

In plant cells

Question 41

What is the function of glyoxysomes?

Answer 41

To convert stored lipids to carbohydrates.

Question 42

Which cell types contain vacuoles?

Answer 42

Plants, fungi and protists

Question 43

From where does the vacuole arise?

Answer 43

The ER and Golgi body

Question 44

What is the general function of the vacuole?

Answer 44

To give structure and prevent bursting.

Question 45

What is the function of the vacuole in petals?

Answer 45

It contains pigment that attracts pollinators and so assists in reproduction.

Question 46

What is the function of vacuoles in seeds?

Answer 46

Hydrolyses proteins to monomers for food during development.

Question 47

What is the function of the cytoskeleton?

Answer 47

- To support the cell and maintain shape - Holds organelles in position - Helps organelles move around the cell - Involved in cytoplasmic streaming - Anchor cell

Question 48

What is the cytoskeleton comprised of?

Answer 48

Microfilaments, intermediate filaments and microtubules.

Question 49

What are the functions of microfilaments?

Answer 49

- They allow movement and determine and stabilise cell shape. - Involved in cytoplasmic streaming - Involved in the formation of pseudopodia

Question 50

What are microfilaments comprised of?

Answer 50

Monomers of actin

Question 51

What are the functions of intermediate filaments?

Answer 51

- Anchor cells in place | - Resist tension by stretching through the cytoplasm and connecting to desmosomes.

Question 52

What is the structure of microtubules?

Answer 52

Long, hollow unbranched cylinders of tubulin.

Question 53

What is the function of microtubules?

Answer 53

They act as a framework for motor proteins to move within the cell.

Question 54

Where do microtubules radiate from?

Answer 54

The microtubule organising centre (MTOC).

Question 55

What are the two ways of determining cause and effect?

Answer 55

- Inhibition (inhibit A and see if B still occurs) | - Mutation (examine cell that lacks A and see if B still occurs)

Question 56

What is the plant cell wall comprised of?

Answer 56

Cellulose fibres embedded in polysaccharides.

Question 57

What are the functions of the plant cell wall?

Answer 57

- Provides support for cell | - Creates barrier to infection by fungi

Question 58

What are the cytoplasm of adjacent cells joined by?

Answer 58

Plasmodesmata

Question 59

What cells are surrounded by an extracellular matrix?

Answer 59

Animal cells

Question 60

What is the extracellular matrix comprised of?

Answer 60

Collagen, proteoglycans and proteins.

Question 61

What are the functions of the extracellular matrix?

Answer 61

- Contributes physical properties of cartilage and skin - Filters materials passing between tissues - Orients cell movement in embryonic development and tissue repair - Cell signalling