cell structure & microscopy

Question 1

what is the structure of the nucleus?

Answer 1

• surrounded by 2 membranes called a nuclear envelope
• envelope contains nuclear pores
• nucleus contains linear DNA
• darker staining area called a nucleolus

Question 2

what is the function of the nucleus?

Answer 2

produces mRNA, tRNA and ribosome RNA- the pores allow them to leave the nucleus and into the cell
contains genetic material and codes

Question 3

what is the structure of the ribosome?

Answer 3

free in the cytoplasm or attatched to the RER
made of RNA and proteins
80s in eukaryotic, 70s in prokaryotic

Question 4

what is the function of the ribosome?

Answer 4

site of protein synthesis

Question 5

what is the structure of the mitochondria?

Answer 5

2 membranes (envelope)
1-10 um in length
inner membrane is folded (cristae) for a larger SA
matrix contains lipids, ribosome and dna so it can produce its own proteins

Question 6

what is the function of the mitochondria?

Answer 6

aerobic respiration (ATP)

Question 7

what is the structure of the cell wall (plant cells) ?

Answer 7

rigid- made of cellulose embedded in a matrix
middle lamella thin layer boundry
algae ( cellulose) fungi (chilin)

Question 8

what is the function of a cell wall (plant cells) ?

Answer 8

-provides mechanical strength
-prevents cell from bursting when water moves in
-freely permeable

Question 9

what is the structure of the vacuole?

Answer 9

• surrounded by a membrane called a tonoplast
• vacuole is fluid filled

Question 10

what is the function of the vacuole?

Answer 10

• tonoplast controls the exchange of material between the vacuole+ cytoplasm
• make cell turgid for support

Question 11

what is the structure of the chloroplast?

Answer 11

• surrounded by 2 layers of membrane (envelope)
• stroma (jelly like substance)
• membranes forming flattening sacks called thylakoid membranes- stacks=grana
• small starch grains+ lipids in the stroma

Question 12

what is the function of the chloroplast?

Answer 12

photosynthesis

Question 13

what is the structure of the lysosome?

Answer 13

• have a single membrane
• contain hydrolyctic (digestive) enzymes- protease, lipase and lysozymes
• size up to 1um

Question 14

what is the function of the lysosome?

Answer 14

• digest old cell organelles
• hydrolyse material ingested by phagocytic cells
• release enzymes to the outside of the cell

Question 15

what is the structure of the golgi apparatus?

Answer 15

• formed in vesicles which bud off the rough ER
• broken down at the other end to form golgi vesicles

Question 16

what is the function of the golgi apparatus?

Answer 16

• molecules ( proteins and lipids) are processed and sorted into golgi vesicles for transport
• make lysosomes

Question 17

what is the structure of the endoplastic reticulum?

Answer 17

membrane organelle
can have ribosomes attatched ( RER)

Question 18

what is the function of the endoplastic reticulum?

Answer 18

RER- provides a large surface area for synthesis of proteins and glycoproteins- then transports them through the cell
makes golgi apparatus
SER- synthesises proteins, stores+ transports lipids and carbohydrates

Question 19

what is the structure of the cell surface membrane?

Answer 19

7nm thick
plasma membrane

Question 20

what is the function of the cell surface membrane?

Answer 20

partially permeable which controls exchange between the cell and the environment

Question 21

what is the division of labour?

Answer 21

how proteins are made, packaged and transported throughout the cell

Question 22

what are the steps for the division of labour?

Answer 22

1) DNA in the nucleus contain instructions to make proteins
2) Protein synthesis in the ribosome
3) Protein transported through RER
4) Protein molecules are pinched off in vesicles and are transported towards the golgi apparatus
5) Vesicles fuses with golgi apparatus
6) Golgi apparatus process and packages protein ready to release
7) Protein molecules are then pinched off in vesicles from ga and transported towards the plasma membrane
8) Vesicle fuse with plasma membrane
9) Protein leaves cell by exocytosis

Question 23

what is the function of a sperm cell?

Answer 23

delivers genetic material to the female gamete

Question 24

what are the adaptations of a sperm cell?

Answer 24

-haploid genome to combine with female dna
- many mitochondria for energy
-undulipodium acts as a tail to propell cell
- acrosome in the head is filled with digestive enzymes to break down layer of the egg

Question 25

what is the function of the egg (ovum) cell?

Answer 25

receives dna from sperm and provides nutrients to developing embyro

Question 26

what are the adaptations of an egg cell?

Answer 26

- haploid genome to combine with male dna - zona pellucida contains glycoproteins to draw in sperm cells - corona radiata is a protein heavy layer that provides nutrients for the embryo

Question 27

what is the function of the red blood cell?

Answer 27

transport of oxygen in the blood

Question 28

what is the adaptations of the red blood cell?

Answer 28

-bioncave shape for small sa:v ratio - flexible to fit in tiny capillaries - no nucleus or organelles so it can be filled with haemoglobin

Question 29

what is the function of the white blood cell?

Answer 29

central role in the immune system

Question 30

what is the adaptations of the white blood cell?

Answer 30

neutrophils- contain many lysosomes in the cytoplasm to digest pathogens+ multilobed nuclei to fit in small spaces lymphocytes- contain many ribosomes due to their role in producing antibodies/toxins phagocytes- have a cytoskeleton that can change shape of membrane for capturing foreign bodies

Question 31

what is the function of a paliside cell?

Answer 31

responsible for photosynthesis in plant cells

Question 32

what are the adaptations of paliside cells?

Answer 32

- high density of chloroplasts to perform photosynthesis - large vacuole+ cell wall high in cellulose to tax in large volume of water for photosynthesis and support

Question 33

what is the function of root hair cells?

Answer 33

cells in a plant root responsible for absorption of water and ions

Question 34

what is the adaptations of root hair cells?

Answer 34

- long extension that increases surface area to maximise absorption - thin cell walls to reduce diffusion distance - vacuole filled with sap lowers water potential to encourage osmosis ( down a conc gradient)

Question 35

what structures are ALWAYS present in a prokaryotic cell?

Answer 35

circular dna, cell wall, ribosomes, cytoplasm, cell surface membrane

Question 36

what structures are SOMETIMES present in a prokaryotic cell?

Answer 36

capsule, mesosome, flagellum, pili, plasmid, infolding plasma membrane

Question 37

what is the function of a mesosome?

Answer 37

infolding of the plasma membrane, may have enzymes on for respiration, large surface area for enzymes

Question 38

what is the function of a pili?

Answer 38

for attatchment to other cell surfaces for sexual reproduction- can supply genetic material for antibiotic resistant bacteria

Question 39

what is the function of a cell wall?

Answer 39

made of murein for structure

Question 40

what is the function of the flagellum?

Answer 40

tail used for locomotion

Question 41

what is the function of the capsule?

Answer 41

mucus layer of slime, protects the cell and ensures it doesnt dry out

Question 42

what is the function of the plasma membrane?

Answer 42

barrier- diffusion for some substances

Question 43

what is the function of the circular dna?

Answer 43

contains most of the genetic material

Question 44

what is the function of the plasmid?

Answer 44

contains SOME genetic material for reproduction