cell structure

Question 1

Name two features of plant cells that are not features of animal cells.

Answer 1

cellulose / cell, wall ;
chloroplast(s) ;
starch grain(s) / amyloplast(s) ;
large / permanent, vacuole ;
tonoplast ;
plasmodesma(ta) ;

Question 2

Name one structure present in animal cells that is not present in plant cells.

Answer 2

centriole / glycogen granule ;

Question 3

The cytoskeleton in cells consists of microtubules and microfilaments.
Describe the roles of the cytoskeleton.

Answer 3

1 (whole) cell, support / stability / scaffolding /
maintain shape ;
2 movement of, cilia / flagella / undulipodia OR use
of cilia / flagellum / undulipodium to move cell ;
3 changing shape of cell / cytokinesis / pseudopodia /
phagocytosis / endocytosis / exocytosis /
muscle contraction ;
4 (named) organelles, moved / held in place ;
5 movement of, chromosomes / chromatids / (m)RNA ;

Question 4

The pancreas is an organ that secretes protease enzymes. Outline how the organelles in pancreatic cells work together to produce and release these protein molecules from the cells.

Answer 4

1 nucleus , contains gene (for protein) / site of
transcription / produces mRNA ;
2 ribosomes / rough endoplasmic reticulum / RER, site
of, protein synthesis / translation ;
3 vesicles for transport (of protein) ;
4 Golgi (apparatus / body), processes / modifies /
(re)packages, proteins ;
5 (vesicles) fuse to, cell surface / plasma, membrane ;
QWC
ribosomes
rough endoplasmic reticulum (NOT RER for QWC)
transcription (and derivatives)
translation (and derivatives)
golgi
vesicles
plasma membrane / cell surface membrane

Question 5

The structure of cells is usually adapted to carry out their functions. The scientist used an electron microscope to look for further evidence to support the mechanism involved in loading sucrose into the sieve tubes.
Suggest what evidence the scientist might expect to see in companion cells, using an electron microscope.

Answer 5

many / large, mitochondria ;
plasmodesmata (between companion cell
 and sieve tube) / described ;
many ribosomes / extensive RER ;
many proteins in the, plasma / cell surface, membrane ;

Question 6

The detailed structure of cells visible only with an electron microscope.

Answer 6

ultrastructure

Question 7

A student suggested that the details of component mitochondria could be seen clearly with a very good light microscope.Explain why the student is not correct.

Answer 7

C / mitochondrion / cristae, too small ;
resolution (of light microscope), not high (enough)
OR idea of only, 0.2µm / 200nm ;
wavelength of light too long ;

Question 8

Staining is a process often used in microscopy.Describe the advantages of staining specimens to be viewed under a microscope.

Answer 8

makes visible / easier to see / see more detail ;
(staining) provides / increases, contrast ;
identify / recognise, cell types / organelles / parts of cell ;
identify / recognise, different (named), compounds /
molecules ;

Question 9

State the functions of the components labelled mitochondria and smooth endoplasmic reticulum

Answer 9

mitochondrion
(aerobic) respiration / producing ATP / release energy SER / smooth endoplasmic reticulum
transport / production / processing, of, fats / lipids /
steroids / carbohydrates ;

Question 10

Name one feature that would be present in the cytoplasm of a prokaryotic cell that is not found in a eukaryotic cell.

Answer 10

(free / circular / naked) DNA / genetic material / nucleoid ;
plasmid ;
18nm / 70S / smaller, ribosomes ;

Question 11

Suggest one function of the flagellum in sponge cells

Answer 11

idea of: create flow of water / move water ;

Question 12

Suggest one possible role for the collar of mucus in the cell.

Answer 12

strain / filter (the water) OR trap particles ;

to catch food (particles)

Question 13

Explain the difference between magnification and resolution.

Answer 13

magnification is
the number of times larger the image is compared to
the object ;
resolution is
ability to, distinguish / differentiate between, two separate
points
OR
the, level / degree, of detail that can be seen ;

Question 14

State the resolution that can be achieved by each of the following types of microscope.
light microscope
transmission electron microscope

Answer 14

light 50 - 200 nm / 0.05 - 0.2 m ;

TEM 0.05 - 1.0 nm ;

Question 15

A student stated that Fig. 4.1 was taken using a scanning electron microscope.
What evidence supports the student’s statement?

Answer 15

3 dimensional / 3D, (image) ;

can see the surface (detail) ;

Question 16

State the function of the nuclear pores.

Answer 16

allow communication between nucleus and cytoplasm
or
allow, molecules / named substances, to,
enter / leave (the nucleus) ;

Question 17

State two features of a eukaryotic cell, other than nuclear pores, that would not be visible using medium power of a light microscope.

Answer 17

(named) membranes / phospholipid bilayer ;
ribosomes ;
Golgi ;
endoplasmic reticulum / ER / RER / SER ;
cytoskeleton / microtubules / microfilaments / spindle fibres ;
centrioles ;
vesicles / lysosomes ;
mitochondria ;

Question 18

State one function of the Golgi apparatus.

Answer 18

production of vesicles / packaging proteins ;
modification of / processing of / adding carbohydrate to ,
proteins ;
production of lysosomes ;

Question 19

Suggest why the nuclear envelope contains pores.

Answer 19

allow movement (of substances) in or out of nucleus ;
correctly named substance (entering or leaving nucleus) ;
ref to correct destination of substance

Question 20

State the function of the lysosomes.

Answer 20

contain / release , lysins / lytic enzymes /
hydrolytic enzymes / digestive enzymes ;
digest / break down , organelles / foreign objects / toxins /
cells / pathogens ;
apoptosis / autolysis / described ;

Question 21

Explain why the meristematic tissue needed to be stained for this investigation.

Answer 21

1 chromosomes / chromatin / nucleus ,
can be seen / are visible ;
2 determine / distinguish between ,
different stages (of mitosis / division / cell cycle) ;
3 (staining) provide contrast (between cell structures) /
AW ;
4 (because) different , structures / chemicals ,
take up different amounts of stain ;

Question 22

Suggest two roles of the cytoskeleton

Answer 22

1 provides, strength / stability / support (cell) ;
2 determines shape / changes shape / moves membrane
(for endo / exocytosis) ;
3 movement of, organelles / named organelle /
RNA / protein / chromosomes / chromatids ;
4 attachment to / hold, organelles / named organelle, in place;
5 make up, centrioles / spindle fibres ;

Question 23

It has been suggested that the mesosome has the same role as mitochondria in eukaryotic cells.
Suggest the role of the mesosome in prokaryotic cells, such as bacteria.

Answer 23

production of ATP ;

aerobic respiration ;

Question 24

State the process that is carried out in each of the organelles listed below.
ribosome
chloroplast

Answer 24

protein synthesis / translation ;

photosynthesis / described ;

Question 25

State two reasons why the blood smear has been stained.

Answer 25

visible / can be seen / increase contrast ;
named example of what is now visible (after
staining) ;

Question 26

Suggest one detail that would be made visible if the micrograph were taken using:
a scanning electron microscope
a transmission electron microscope.

Answer 26

3D shape can be seen / greater depth of field ;
can see, surface features / detail ;
smaller / named, organelle (becomes visible) ;
shapes / details of organelles ;

Question 27

Suggest why some cells did not stain blue at 20 °C.

Answer 27

cells, dead / not respiring ;

no, (metabolic) energy / ATP, to take up stain ;

Question 28

Structures C and E are examples of the same organelle, mitochondrion.
Suggest why E looks so different to C.

Answer 28

(mitochondria) vary in shape ;
longer than wide ;
cut in different planes / angles / AW ;
just divided / growing ;
artefact / deformed during preparation of section ;

Question 29

Outline the sequence of events following the production of extracellular proteins that leads to their release from the cell.

Answer 29

proteins moved to Golgi (apparatus / body) ;
processed / modified / AW ;
into vesicles ;
(vesicle) moved to, plasma / cell surface, membrane ;
(vesicles) fuse with membrane ;
exocytosis ;

Question 30

State two features that are present in the eukaryotic cells of plants that are absent from the cells of insects

Answer 30

chloroplast(s) ;
large / permanent , vacuole ;
tonoplast ;
starch (grains) ;