Cell structure

Question 1

eukaryotic cell

Answer 1

cells that contain a nucleus and organelles enclosed by a plasma membrane.

Question 2

ultrastructure

Answer 2

a fine structure within a cell that can only be seen with a high magnification includes e.g organelles that allow the cell to function

Question 3

non membranous organelles

Answer 3

ribosome 
centrioles
cilia and flagella 
cytoskeleton
plant cell wall

Question 4

3 similarities between a plant and animal cell

Answer 4

both eukaryotic cells
both have membrane bound organelles
both have a nucleus

Question 5

3 differences between a plant and animal cell

Answer 5

plant cells have:
   * cell wall 
   * chloroplast
   * vacuole
plant cells are usually larger than animals (10-100 compared to 10 to 30 micrometres)

Question 6

prokaryotic cell

Answer 6

single celled organism without a nucleus or membrane bound organisms

Question 7

examples of prokaryotic cells

Answer 7

eubacteria

archea

Question 8

examples of eukaryotic cells

Answer 8

animals
plants
fungi
protoctista (algae)

Question 9

size of prokaryotic cell

Answer 9

0.1-10 micrometers

Question 10

size of eukaryotic cells

Answer 10

20-30 micrometers

Question 11

outline structure and function of the nucleus

Answer 11

structure 
1. double membrane
2. has nuclear pores 
3. contains chromatin made up of DNA and proteins
4. often contains nucleolus 
function 
1. controls cell activity 
2. contains code for proteins 
3. pores allow RNA to move between nucleus and cytoplasm

Question 12

outline structure and function of nucleolus

Answer 12

1. structure in the nucleus responsible for the production of RNA and ribosomes
   (composed of RNA which is used to produce ribosomal RNA which combines with protein to form ribosome)

Question 13

outline structure and function of the nuclear envelope

Answer 13

1. allows molecules to move between nucleus and the cytoplasm
2. protects the nucleus from damage in cytoplasm

Question 14

outline structure and function of rough endoplasmic reticulum

Answer 14

structure
1. membranes enclosing flattened sacs called cisternae
2. covered in ribosomes
function
1. transports proteins made in ribosomes on surface

Question 15

outline structure and function of smooth endoplasmic reticulum

Answer 15

structure
1. membranes enclosing flattened sacs called cisternae
function
1. synthesizes, stores and transports lipids and carbohydrates

Question 16

outline structure and function of the Golgi apparatus

Answer 16

structure
1. group of fluid filled, membrane bound flattened sacs
2. vesicles often found on the outside
function
modifies and packages proteins and pinches them into vesicles for transport

Question 17

outline structure and function of ribosome

Answer 17

structure 
1. small organelle that either floats free in cytoplasm or is attached to ribosome 
2. made of proteins and RNA
3. not membrane bound 
function 
1. site where proteins are made

Question 18

outline structure and function of mitochondrion

Answer 18

structure
1. have own nucleus
2. usually oval shape
3. has double membrane - inner one folds up into structures called cristae
3. matrix full of enzymes involved in respiration
function
1. site where ATP is produced in respiration
2. in large numbers in the cell and very active

Question 19

outline structure and function of lysozymes

Answer 19

structure 
1. round organelle surrounded by a membrane with no clear internal structure 
function 
1. contain digestive enzymes contained separate from cytoplasm in the membrane which can be used to break down invading cell or dead components of the cell

Question 20

outline structure and function of chloroplast

Answer 20

structure

1. small flattened sac found in plants
2. surrounded by a double membrane
3. has membranes inside called thylakoid membranes stacked to form grana
4. grana are linked together by lamellae (fibers of thylakoid)

Question 21

outline the function and structure of plasma membrane

Answer 21

structure
1. membrane found of surface of animal cells and behind cell wall of plant and fungi cells
2. made up of mainly proteins and lipids
function
1. regulates movement of substances into and out of the cell
2. has receptor molecules which respond to chemicals such as hormones

Question 22

outline the structure and function of centrioles

Answer 22

structure
1. small hollow cylinders made up of microtubules 2. found in animals but only some plants
function
1. involved in separation of chromosomes in cell division

Question 23

outline the structure and function of cell wall

Answer 23

structure
1. rigid structure surrounding the plant
2. made up of mainly cellulose or chitin
function
1. supports the cell

Question 24

outline structure and function of flagella

Answer 24

structure
1. stick out of cell surface and are surrounded by the plasma membrane
2. two microtubules in the center and 9 pairs around the edge
function
1. microtubules contract to make cell move
2. like an outward propeller to make cell move

Question 25

outline structure and function of cilia

Answer 25

structure 1. small hair like structures found on the surface of some animal cells 2. in the cross section they have 9 pairs of microtubules around the edge with one pair in the middle structure 1. microtubules allow cilia to move the cell uses this to move substances along its surface

Question 26

outline the 3 structures of the cytoskeleton

Answer 26

set of fibers essential for shape and stability of cell microtubules - globular tubular proteins polymerized to form tubes which act like a scaffold which determines shape of the cell microfilaments - made of actin (a protein) forming contractile fibers intermediate filaments - composed of fibrous subunits - keratin coiled together

Question 27

describe the functions of the microfilaments in the cell

Answer 27

1. microfilaments involved in cytokinesis - pinching effect actin ring between two cells pulled on shrinking and pulling membrane with it splitting cell in two. 2. microfilaments anchored to proteins in cell membrane - allowed to push and pull on membrane to move cell. subunits can be added to protein depending on rate of addition cell then moves in specific direction

Question 28

describe the functions of microtubules in the cell

Answer 28

1. cilia and flagella made of 9 pairs +2 microtubules and are involved of the movement of the whole cell or moving things across cell surface. 2. centrioles composed of microtubules in a triplet circle which are used to move chromosomes in cell division 3. shape of the cell 4. movement of organelles - act as tracts for e.g. vesicles to move along them

Question 29

outline structure and function of cell wall in prokaryotes

Answer 29

``` structure 1. made of peptidoglycan or murein function 1. structure and support for the cell ```

Question 30

outline structure and function of ribosomes in prokaryotes

Answer 30

smaller 70S ribosomes made of two sub units | involved in production of proteins

Question 31

outline structure and function of the bacterial flagellum

Answer 31

structure 1. made of protein flagellin 2. thinner + not 9+2 arrangement

Question 32

outline structure and function of plasmid in prokaryotes

Answer 32

structure 1. small loops of DNA 2. used to swap genetic material between bacteria to evolve fast

Question 33

outline structure and function of bacterial chromosome

Answer 33

contains code for proteins

Question 34

outline structure and function of cytoskeleton in prokaryotes

Answer 34

less complex than in eukaryotes as flagella will propel cell by microfilaments

Question 35

outline structure and function of pili in prokaryotes

Answer 35

protein hairs adhered to surface

Question 36

outline structure and function of slime capsule in prokaryotes

Answer 36

a layer around the cell to prevent it from drying

Question 37

comparison of prokaryotes and eukaryotes

Answer 37

1. Reproduction: EC- asexual or sexual. PC- Binary fission 2. Cell size: EC- 20-40 um diameter PC- usually 0.5- 5 um diameter 3. location of genetic material: EC- In the nucleus PC- free in the cytoplasm