1.2 Cell structure and organisation

Question 1

define eukaryotic cell.

Answer 1

A type of cell that contains a nucleus along with membrane bound organelles.

Question 2

describe the structure of mitochondria.

Answer 2

Surrounded by a double membrane (mitochondrial envelope)
folded in a membrane forms cristae (large surface area)
fluid matrix contains mitochondrial DNA, respiratory enzymes, lipids, and proteins. (enzymes for respiration)

Question 3

describe the function of mitochondria.

Answer 3

site of aerobic respiration to produce ATP

Question 4

describe the structure of the endoplasmic reticulum (ER)

Answer 4

series of flattened membrane bound sacs (cisternae) within the cytoplasm, continuous with the nucleus envelope

Question 5

describe the function of the smooth endoplasmic reticulum (SER)

Answer 5

membrane bound sacs - producing and processing lipids (lipid synthesis)

Question 6

describe the function of the rough endoplasmic reticulum (RER).

Answer 6

many ribosomes attached for protein synthesis and transport
(it folds and processes proteins made on the ribosomes).

Question 7

describe the structure of the Golgi body.

Answer 7

planar stack of membrane bound, flattened sacks.
cis face aligns with RER
Molecules are processed in cisternae
Vesicles leave via trans faced by exocytosis

Question 8

describe the function of the Golgi body apparatus.

Answer 8

modifies and packages proteins for export
Synthesis glycoproteins
Produces secreting enzymes
Transporting - storing lipids

Question 9

describe the function of ribosomes.

Answer 9

site of protein synthesis production
Large sub unit joins amino acids
Small subunit reads rRNA

Question 10

describe the structure of ribosomes

Answer 10

made from rRNA and proteins
found free in the cytoplasm or associated with the RER

Question 11

describe the structure and function of lysosomes.

Answer 11

fluid-filled vesicles surrounded by a single membrane containing enzymes

Role in phagocytosis digesting unwanted materials in the cytoplasm

Question 12

describe the structure of centrioles.

Answer 12

cylindrical structure
Organised into microtubules in a 9+0 pattern
found in pairs in the centrosomes.

Question 13

describe the function of centrioles.

Answer 13

Migrate to oppose poles of the cell during prophase.
Involved in the organisation of spindle fibres.

Question 14

describe the structure of a chloroplast.

Answer 14

Disk shaped surrounded by double membrane.

Thylakoids - flattened disks stacked to form grana.

Grana - contain photosystems with chlorophyll.

Intergranal lamellae - tubes attach thylakoids in adjacent grana.

Stroma - fluid-filled matrix.

Question 15

what is the function of a chloroplast.

Answer 15

site of photosynthesis.

Question 16

describe the structure of the permanent vacuole in plants.

Answer 16

surrounded by a single membrane called tonoplast.
Contains cell sap (mineral ions, water, enzymes, soluble pigments)

Question 17

describe the function of the permanent vacuole in plants.

Answer 17

controls turgor pressure
water storage
isolates harmful waste products
maintains pH

Question 18

Describe the structure of the nucleus.

Answer 18

surrounded by nuclear envelope which is semi permeable and double membraned.
nuclear pores allow substances to enter and exit.
Dense nucleolus (made of RNA and proteins) assembles ribosomes which is the site of ribosome production.

Question 19

describe the function of the nucleus.

Answer 19

contains DNA coiled around the chromatin into chromosomes.
coordinates cellular activities.

Question 20

what is chromatin?

Answer 20

a DNA protein complex found in eukaryotic cells.
The DNA coils bound to protein which codes for protein synthesis.

Question 21

excluding the envelope, name 2 other things that surround the nucleus.

Answer 21

chromatin and a nucleolus which is the site of ribosome production (assembles the cells ribosomes)

Question 22

what is the function of the nucleolus.

Answer 22

production of rRNA and ribosomes.

Question 23

what is the structure and function of the nuclear envelope?

Answer 23

a double membrane with pores that allows mRNA and ribosomes out of the nucleus.

Question 24

define plasmodesmata

Answer 24

microscopic channels between plant cell walls that facilitate communication and symplastic transport.

Question 25

define prokaryotic cell

Answer 25

a type of cell that doesn't contain any membrane-bound organelles or a 'true' nucleus

Question 26

describe the structure and function of the flagella in prokaryotic cells.

Answer 26

A type of cell that doesn't contain any membrane-bound organelles or a 'true' nucleus. long whip-like structure which rotates to move the cell. sensory organ

Question 27

how is genetic information stored in prokaryotes?

Answer 27

plasmids - small rings of DNA that carry non-essential genes, exchanged between bacterial cells via conjugation. Loop of DNA - circular DNA stored in the nucleoid region of the cell.

Question 28

describe the structure and function of pili in prokaryotic cells.

Answer 28

Half like microfibres made of pilin that extend through the cell wall. Enable the attachment of bacteria to each other and to other surfaces.

Question 29

describe the structure and function of the mesosome.

Answer 29

It is the infolds of the cell membrane. increase surface area of the cell, aiding cellular respiration.

Question 30

what is the function of the capsule in prokaryotic cells?

Answer 30

Protective, slimy layer Helps the cell to retain moisture and adhere to other surfaces.

Question 31

which organelles are found in both eukaryotic and prokaryotic cells?

Answer 31

cell membrane cytoplasm with a form of cytoskeleton (cytoskeleton of eukaryotes is more significant) ribosomes

Question 32

name 4 differences between eukaryotic and prokaryotic cells.

Answer 32

Eukaryotes/Prokaryotes DNA in nucleus/DNA free in cytoplasm Ribosomes 80s/Ribosomes 70s Cellulose cell wall/ Peptidoglycan cell wall Mitochondria for aerobic respiration/mesosome for aerobic respiration. Large, often multicellular/ Small, often unicellular

Question 33

contrast 4 points about eukaryotic plant and animal cells.

Answer 33

plant/animal cellulose cell wall/ no cell wall. Large permanent vacuole/ small temporary vacuoles (vesicles). contain chloroplasts/no chloroplasts. no pseudopodia/some may have pseudopodia.

Question 34

what is a light microscope?

Answer 34

a type of microscope that uses a series of lenses to magnify the visible light reflecting off a specimen.

Question 35

how can the magnification of an image be calculated?

Answer 35

magnification = size of image/ size of specimen

Question 36

describe cell theory

Answer 36

the cell is the fundamental unit of all life forms. new cells can be formed from existing cells. cells contain genetic material which can be transferred to daughter cells.

Question 37

what is a virus?

Answer 37

a non-living microorganism that consists of genetic material surrounded by a protein husk.

Question 38

how do viruses differ from prokaryotic and eukaryotic cells? (5 points)

Answer 38

Virus/prokaryotic and eukaryotic non-living/living smaller simpler structure/larger complex structure genetic material in from of DNA and RNA/ genetic material in form of DNA only reproduce within a host cell/ independent cell division, sexual or asexual. no ribosomes/contain ribosomes

Question 39

how are multicellular organisms organised?

Answer 39

many cells make up a tissue many tissues make up an organ many organs make up an organ system

Question 40

define tissue

Answer 40

a group of cells working together to carry out a specific function.

Question 41

define organ

Answer 41

a group of tissues working together to carry out a specific function

Question 42

define organ system

Answer 42

a group of organs working together to carry out a specific function

Question 43

what is the structure of the cytoplasm?

Answer 43

no structure - fluid cytosol contains dissolved substances and enzymes

Question 44

what is the function of the cytoplasm?

Answer 44

site of cell reactions e.g. anaerobic respiration