DNA and cells - EUKARYOTES

Question 1

What kingdoms are eukaryotic?

Answer 1

Animals, plants, fungi, protoctists

Question 2

Compare and contrast eukaryotic and prokaryotic cells

Answer 2

• E have a nucleus, membrane bound organelles and mitochondria whereas P don’t
• E are found in animals, plants, fungi and protoctista whereas P are in bacteria
• In E ribosomes are larger than P (80s vs 70s)
• E have linear DNA whereas P have circular DNA(plasmids)

Question 3

What do plant cells have that animals cells don’t?

Answer 3

Chloroplasts, cell wall, vacuole

Question 4

What is the nuclear envelope and what does it do?

Answer 4

• A double membrane with ribosomes on the surface surrounding the nucleus
• It controls entry and exit

Question 5

What are nuclear pores and what do they do?

Answer 5

• Tiny holes on the surface of the nuclear envelope
• They allow passage of large molecules e.g.mRNA/ribosomes

Question 6

What is nucleoplasm?

Answer 6

• The cytoplasm of the nucleus

Question 7

What is the nucleolus and what does it do?

Answer 7

• Synthesises RNA

Question 8

Describe the structure of the mitochondria

Answer 8

• Rod shaped
• 1-10µm in length
• Has a double membrane which controls entry and exit
• The inner membrane forms extensions/cristae
• The cristae has a large surface area for attachment of enzymes
• The matrix is gel-like which contains proteins, lipids, ribosomes, DNA and respiratory enzymes

Question 9

What is the function of the mitochondria?

Answer 9

• Site of respiration
• Production of ATP

Question 10

What is the function of the nucleus?

Answer 10

• Acts as the control centre of the cell through production of m/tRNA
• Holds genetic material (long term)
• Manufactures rRNA and ribosomes

Question 11

What are ribosomes?

Answer 11

• Small organelles found in the cytoplasm
• Associated with the rough endoplasmic reticulum
• Involved in protein synthesis

Question 12

Describe the structure of a ribosome

Answer 12

Made of rRNA and proteins/amino acids

Question 13

Describe the structure of the cell membrane

Answer 13

• Composed of a phospholipid bilayer
• Has receptors which allow it to interact with other proteins, helping with cell recognition and signalling

Question 14

What does the cell membrane do?

Answer 14

Controls the movement of substances into and out the cell

Question 15

Describe the structure of the cytoplasm

Answer 15

• Jelly like substance which surrounds organelles
• Contains dissolved molecules that take part in metabolic reactions

Question 16

What is the function of the cytoplasm?

Answer 16

• Contains dissolved molecules
• Site of chemical reactions

Question 17

Where are lysosomes most commonly found?

Answer 17

In secretory cells

Question 18

What is the structure of a lysosome?

Answer 18

• Formed of a hydrolytic enzyme mixture surrounded by a lipid layer and a membrane
• Also contains enzymes that hydrolyse cell walls of bacteria

Question 19

What is the function of a lysosome?

Answer 19

• Aids secretion
• Hydrolyses material ingested by phagocytic cells
• Releases enzymes
• Digests old/damaged cells
• Completely breaks down cells after they have died

Question 20

What is the difference between smooth and rough endoplasmic reticulum?

Answer 20

• Rough endoplasmic reticulum has ribosomes on the surface whereas Smooth endoplasmic reticulum don’t
• Smooth endoplasmic reticulum has a tubular appearance

Question 21

Describe the structure of the endoplasmic reticulum

Answer 21

• Continuous with the nuclear envelope
• It is a network of tubules/ flattened sacs called cisternae

Question 22

What is the function of the rough endoplasmic reticulum?

Answer 22

• Provides the pathway for transport of materials
• Has a large surface area for protein synthesis

Question 23

What is the function of the smooth endoplasmic reticulum?

Answer 23

• Synthesises, stores and transports lipids/carbohydrates

Question 24

Describe the structure of the golgi apparatus?

Answer 24

• A stack of membranes (looks like naan bread)
• Modifies proteins as they are passed through

Question 25

What is the primary function of the golgi apparatus?

Answer 25

• Lipids are added to make lipoproteins
• Carbs are made into glycoproteins
• Polypeptides are made into proteins

Question 26

What is the secondary function of the golgi apparatus?

Answer 26

• Produces secretory enzymes
  secrete carbs, transport/modify/store lipids and form lysosomes

Question 27

What is the structure of a chloroplast?

Answer 27

• Chloroplast envelope - has a double plasma membrane(highly selective
• Thylakoids - contains chlorophyll
• Grana - stacks of 100 disk shaped thylakoids
• Stroma - fluid filled matrix which contains enzymes, starch grains, DNA and ribosomes

Question 28

What is the function of the chloroplasts?

Answer 28

Site of photosynthesis

Question 29

What are adaptations of the chloroplasts?

Answer 29

• Granal membranes provide large surface area for attachment of chlorophyll
• Fluid contains enzymes
• Chloroplasts contain DNA + ribosomes for quick and easy manufacture of proteins.

Question 30

Are chloroplasts found in plant cells, animal cells, or both

Answer 30

Plant cells only

Question 31

Describe the structure of the cell wall

Answer 31

• Microfibrils of cellulose(matrix)/chitin in fungi
  -Strong because of fibrils
  -Thin layer called lamella marks the boundary between adjacent cells

Question 32

What is the function of the cell wall?

Answer 32

To provide strength (especially during osmosis)

Question 33

Is the cell wall found in plant cells, animal cells, or both?

Answer 33

Plant cells only

Question 34

Is the vacuole found in plant cells, animal cells, or both?

Answer 34

Plant cells only

Question 35

Describe the structure of a vacuole

Answer 35

• Fluid filled sac bounded by a single membrane called the tonoplast

Question 36

What does the vacuole contain?

Answer 36

• Mineral salts
• Sugars
• Amino acids
• Metabolic wastes
• Pigments

Question 37

What is the function of the vacuole?

Answer 37

• Maintains cell turgidity
• Contains an energy store and can contain pigments that make petals coloured (in order to attract pollinating insects)