Cells/cell structure

Question 1

Differences between eukaryotic and prokaryotic cells

Answer 1

• Prokaryotic cells are far smaller
• Eukaryotic cells have a nucleus whereas prokaryotic cells do not.
• Prokaryotic cells have no membrane bound organelles.
• Prokaryotic cells have 70S ribosomes and eukaryotic have 80S
• Prokaryotic cells have an outer layer called a capsule for protection
• DNA in prokaryotic cells is circular & extra plasmids, whereas it is linear in eukaryotic cells

Question 2

Similarities between prokaryotic and eukaryotic cells

Answer 2

• Both have cytoplasm
• Both have a cell membrane

Question 3

ORGANELLE FLASHCARDS IN FOLDER

Question 4

What are vesicles?

Answer 4

Sphere of phospholipid bilateral that transport substances from one part of the cell to another

Question 5

What is the endosymbiotic theory?

Answer 5

Bacterium engulfed by a ‘host cell’ and evolved into the mitochondria and chloroplasts

Question 6

Evidence of endosymbiotic theory

Answer 6

• Some organelles have double membranes (outer membrane may be vesicular in origin)
• Reproduction occurs in a fission-like process
• Has own DNA which is circular
• Have 70S ribosomes

Question 7

What is a tissue?

Answer 7

Group of similar cells organised in a structural unit

Question 8

What is an organ?

Answer 8

Group of different tissues that work together to perform a specific function

Question 9

What is an organ system?

Answer 9

Group of different organs that work together to perform a specific function

Question 10

Features of a virus

Answer 10

• Genetic material in the form of RNA
• Matrix
• Capsid
• Lipid envelope
• Attachment protein

Question 11

What is the process of virus replication?

Answer 11

1. Virus attaches to host cell via receptors on the host cell surface membrane
2. Virus injects genetic material into host, used to synthesise viral proteins
3. New virus particles assembled
4. New viruses burst out of, and damage/destroy, host cell

Question 12

What are the stages of the cell cycle, starting from the beginning of interphase?

Answer 12

• G1 - cellular contents duplicated
• S - Each of the 46 chromosomes duplicated
• G2 - cell ‘double checks’ duplicated chromosomes for error, making necessary repairs
• Mitosis
• Cytokinesis

Question 13

What are the stages of mitosis?

Answer 13

1. Prophase
2. Metaphase
3. Anaphase
4. Telophase

Question 14

What happens during prophase?

Answer 14

• longest phase
• chromosomes condense
• centrioles move to opposite poles of cell
• spindle fibres start to develop
• nuclear envelope disintegrates and nucleolus disappears

Question 15

What happens during metaphase?

Answer 15

• Chromosomes attach to spindle fibres by their centromeres
• They line up at right angles along the equator of the cell

Question 16

What happens during anaphase?

Answer 16

• Stage is very fast
• Centromeres divide into 2
• Spindle fibres shorten and pull chromatids to opposite poles of the cell

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Question 17

What happens during telophase?

Answer 17

• Chromatids referred to as chromosomes again
• Chromosomes lengthen and uncoil
• Spindle disintegrates
• Nuclear envelope reforms and nucleolus reappears

Question 18

What is the importance of cell division?

Answer 18

Growth
Repair/replacement
Reproduction

Question 19

What is mitosis?

Answer 19

Nuclear division that produces two daughter nuclei that are genetically identical to each other and the parent nuclei

Question 20

What are centrioles and what is their structure/function?

Answer 20

• Small hollow cylinders
• A centrosome = 2 centrioles
• Form network of fine fibres in the cytoplasm called the cytoskeleton
• Support cell’s shape
• Organises and moves organelles

Question 21

What is the mitotic index?

Answer 21

The ratio of number of cells undergoing mitosis to the total number of cells

Question 22

Stages of binary fission

Answer 22

1. Cell replicates it’s DNA
2. Cytoplasmic membrane elongates, separating DNA molecules
3. Cross wall forms; membrane invaginates
4. Cross wall forms completely
5. Daughter cells formed

Question 23

What is cell division in prokaryotic cells called?

Answer 23

Binary fission

Question 24

How is cancer treated?

Answer 24

Killing rapidly dividing cells by blocking part of the cell cycle e.g DNA replication or metaphase

Question 25

What is the problem with cancer treatment?

Answer 25

Can also interfere with the cell cycle of normal cells that also divide rapidly

Question 26

What are plasma membranes formed from?

Answer 26

Phospholipids

Question 27

What are the roles of membranes?

Answer 27

• Separating cell contents from the outside world.
• Separating cell components from cytoplasm.
• Cell recognition and signalling.
• Holding components for some metabolic pathways
• Regulating transport in/out

Question 28

Can lipid soluble molecules travel through phospholipid bilayers?

Answer 28

Yes

Question 29

Can water soluble molecules travel through phospholipid bilayers?

Answer 29

No

Question 30

What are proteins that go all the way through the cell membrane called?

Answer 30

Intrinsic proteins

Question 31

What are proteins embedded in the cell membrane called?

Answer 31

Extrinsic proteins

Question 32

What are the two types of intrinsic protein?

Answer 32

Channel proteins
Carrier proteins

Question 33

What is a glycoprotein?

Answer 33

Protein with a carbohydrate group attached

Question 34

What is a glycolipid?

Answer 34

Lipid which has a carbohydrate attached