Eukaryotic cells

Question 1

What are stem cells?

Answer 1

undifferentiated cells

Question 2

How are specialised cells organised in complex multicellular organisms?

Answer 2

organised into tissues, tissues into organs and organs into systems

Question 3

What is the difference between prokaryotic and eukaryotic cells?

Answer 3

prokaryotic cells have no membrane bound organelles (e.g. nucleus, mitochondria chloroplasts, golgi apparatus, endoplasmic reticulum, vacuole

Question 4

What is in ATP?

Answer 4

Adenine, ribose, 3 phosphate group

Question 5

Describe the structure of the nucleus

Answer 5

Has chromatin which are linear strands of DNA, coiled round histone protein
Contains nuclear envelope and pores which is a double membrane envelope that forms the boundary of the structure
Nucleolus - dense spherical region of protein

Question 6

Describe the function of the nucleus

Answer 6

Manages cells genetic information and controls the cells DNA, which is organised into chromosomes
Nuclear envelope - controls entry and exit of molecules, protecting DNA from damage
Chromatin - contain code for proteins and functional RNAs
Nucleolus and nucleic acid - synthesis of ribosomal RNA and assembly of ribosomes
production of mRNA

Question 7

What is the main polymer that forms a plant cell wall?

Answer 7

cellulose

Question 8

What is the main polymer that forms a fungal cell wall?

Answer 8

chitin

Question 9

Does a bacterial cell have a cell wall?

Answer 9

yes

Question 10

Does a bacterial cell have a cell-surface membrane?

Answer 10

yes

Question 11

What’s one piece of evidence that supports the theory that mitochondria evolved from prokaryotic cells?

Answer 11

have circular DNA 70s ribosomes

Question 12

Why will organelles in drawings of cells appear as different shapes?

Answer 12

at different angles in diagram

Question 13

What is the structure of the rough endoplasmic reticulum?

Answer 13

Tubules and flattened discs of membranes, with ribosomes on outer surface, forming a large surface area

Question 14

What is the function of the rough endoplasmic reticulum?

Answer 14

Efficient synthesis of proteins and glycoproteins which are embedded in membranes or transported

Question 15

What is the structure of the golgi apparatus?

Answer 15

Stack of flattened sacs of membranes, with many enzymes and other proteins embedded in the membrane surfaces

Question 16

What is the function of the golgi apparatus?

Answer 16

Modify proteins and lipids, e.g. adding carbs to form glycoproteins
‘Label’ proteins to allow for sorting and form vesicles of carbohydrate, glycoprotein or lipid
Releases vesicles

Question 17

What is the structure of the golgi vesicles?

Answer 17

Small hollow spheres of membrane

Question 18

What is the function of the golgi vesicles?

Answer 18

transport molecules to cell surface membrane for exocytosis

Question 19

What is the structure of the ribosomes?

Answer 19

Made of two subunits, composed of RNA and proteins

Question 20

What is the function of the ribosomes?

Answer 20

Site of protein synthesis - amino acids joined in correct sequence (read from mRNA)

Question 21

What is the structure of the smooth endoplasmic reticulum?

Answer 21

Large interlinked network of tubules of membrane
No ribosomes on surface

Question 22

What is the function of the smooth endoplasmic reticulum?

Answer 22

Synthesise and store lipids and carbohydrates
Transport manufactured lipids and carbohydrates throughout cell

Question 23

What is the structure of the cell surface membrane?

Answer 23

Phospholipid bilayer with protein channels and transport proteins
Bilayer also contains proteins and glycoproteins, which form attachments to other membranes

Question 24

What is the function of the cell surface membrane?

Answer 24

Bilayer = hydrophobic so only small + non-polar molecules can diffuse across
Contains transport proteins - select which molecules can cross membrane
Fluid - can fuse with other membranes
Contains proteins which control attachment to other membranes

Question 25

What is the structure of lysosomes?

Answer 25

Small spheres of membrane which contain digestive enzymes (including lysozymes)

Question 26

What is the function of lysosomes?

Answer 26

Digest materials brought into the cell in vesicles (e.g. pathogens) Destroy damaged organelles and break down dead cells

Question 27

What is the structure of the mitochondria?

Answer 27

Rod-shaped and large (1-2 μm length) Double membrane Inner is folded into cristae Matrix - fluid containing proteins, circular DNA and 70s ribosomes

Question 28

What is the function of the mitochondria?

Answer 28

Large surface area for attachment of proteins - for final stages of aerobic respiration (synthesis of ATP) Contain many enzymes for intermediate steps in aerobic respiration Some proteins synthesised in organelle

Question 29

What is the structure of the chloroplasts?

Answer 29

Have double membrane Membrane-bound compartments called thylakoids containing chlorophyll stack to form grana Grana joined together by lamellae Contain small circular pieces of DNA and ribosomes

Question 30

What is the function of the chloroplasts?

Answer 30

site of photosynthesis light-dependent stage takes part in the thylakoids light-independent stage take place in stroma DNA and ribosomes used to synthesise proteins needed in chloroplast replication and photosynthesis

Question 31

What is the structure of cell walls?

Answer 31

Narrow threads of cytoplasm (surrounded by cell membrane) called plasmodesmata connect cytoplasm of neighbouring plant cells

Question 32

What is the function of cell walls?

Answer 32

offer structural support to cells prevents bursting under osmotic pressure Acts as barrier to pathogens/external factors, protecting cell from environmental stress

Question 33

What polysaccharide provides structural support in: plant cells bacterial cells

Answer 33

plant = cellulose most bacterial = peptidoglycan

Question 34

What is the level of organisation?

Answer 34

organelle cell tissue organ organ system organism