Eukaryotic cell structure

Question 1

Name the parts of a eukaryotic cell

Answer 1

Nucleus, mitochondria, chloroplasts, ER, golgi apparatus, lysosomes, ribosomes, cell wall, vacuole, cell membrane, cytoplasm

Question 2

Name the parts of the nucleus and describe its main function

Answer 2

Contains genetic material which controls what the cell does.
Nuclear envelope
Nuclear pores
Nucleoplasm
Chromosomes
Nucleolus

Question 3

Describe the function of the nuclear envelope

Answer 3

is a double membrane surrounding the nucleus connected to the ER and controls the entry and exit of materials

Question 4

Describe the function of nuclear pores

Answer 4

allows the transport of large molecules e.g messenger RNA out of the nucleus

Question 5

Describe the function of the nucleoplasm

Answer 5

granular, jelly-like material that fills the nucleus (contains chromosomes)

Question 6

Describe the function of chromosomes

Answer 6

Carries genetic information in the form of genes and made up of nucleic acids and proteins

Question 7

Describe the function of the nucleolus

Answer 7

contains nucleoplasm and makes RNA and ribosomes (can have more than 1 in a nucleus)

Question 8

Name the parts of mitochondria and describe its main function

Answer 8

Site of aerobic respiration and produces ATP.
Double membrane
Cristae
Matrix

Question 9

Describe the the function of the mitochondria’s double membrane

Answer 9

• Controls the entry and exit of material
• Outer membrane: covers like a skin
• Inner membrane: folds into layered structures (increases surface area)

Question 10

Describe the function of the cristae

Answer 10

• Folds inside made by the inner membrane
• Larger surface area (more space) for chemical reactions to take place e.g attachment of enzymes/proteins for respiration

Question 11

Describe the function of the matrix

Answer 11

• Fluid contained within it
• Ribosomes, DNA, proteins and lipids floating in it
• Contains granules which help with ion concentrations
• Produce proteins
• Many enzymes involved in respiration found here

Question 12

Name the parts of chloroplasts and describe its main function

Answer 12

The site of photosynthesis.
Chloroplast envelope
Grana
Stroma

Question 13

Describe the function of the chloroplast envelope

Answer 13

• Similar to the structure of the mitochondrial double membrane
• Very selective in what can leave and enter the chloroplast

Question 14

Describe the function of the grana

Answer 14

• Stacks of discs known as thylakoids (resembles a stack of coins)
• Site of light-dependent reactions of photosynthesis (1st stage of photosynthesis)
• Connected by intergranal thylakoids
• Within thylakoids is chlorophyll

Question 15

Describe the function of the stroma

Answer 15

• Colourless fluid surrounding grana which contains enzymes required for photosynthesis
• DNA and ribosomes are present so proteins can be quickly and easily made for photosynthesis
• Where 2nd stage of photosynthesis (synthesis of sugars) takes place
• Contains starch grains

Question 16

Name the two types of ER and describe the difference in their function

Answer 16

Rough ER -
Contains ribosomes for protein synthesis
Large surface area for protein and glycoprotein synthesis
Pathway for transport of materials e.g proteins
Smooth ER - To store, synthesise and transport lipids and carbohydrates

Question 17

Describe the function of the golgi apparatus

Answer 17

• Produce secretory enzymes, form glycoproteins (made from carbohydrates and proteins) and lysosomes
• Secrete proteins and carbohydrates e.g used in making plant cell walls (for carbohydrates)
• Transports, modifies and stores lipids

Question 18

Describe the function of the cytoplasm

Answer 18

Where chemical reactions e.g anaerobic respiration take place

Question 19

Describe the function of the cell membrane

Answer 19

Controls what goes in and out of the cell

Question 20

Describe the function of lysosomes

Answer 20

• Releases strong enzymes which break down and destroy material around the cell (exocytosis)
• Hydrolyses material ingested by phagocytic cells
• Digest worn out cell organelles so that useful chemicals they are made up of can be reused
• Completely break down cells after they have died (autolysis)

Question 21

Describe the function of ribosomes and the main differences between the two types

Answer 21

• The site of protein synthesis.
• Made up of two subunits (1 large and 1 small) containing ribosomal RNA and proteins.
• 80S ribosomes - found in eukaryotic cells
• 70S ribosomes - found in prokaryotic cells, mitochondria and chloroplasts (slightly smaller)

Question 22

Describe the function of the cell wall

Answer 22

• Gives the cell strength and structure to prevent cell bursting by osmosis
• It is also made of cellulose and other polysaccharides
• Allows water to flow through it
• There is a thin layer called middle lamella which marks boundaries between adjacent cell walls and cements cells adjacent together

Question 23

Describe the function of the vacuole

Answer 23

• Gives the cell structure and stores cell sap (mainly water but also mineral salts, sugars + amino acids)
• Support herbaceous plants + herbaceous parts of woody plants by making cells turgid
• The sugars + amino acids can be temporary food stores
• Pigments may colour petals to attract pollinating insects
• Single membrane around it is the tonoplast