cell structure exam questions Flashcards
Outline the roles of the Golgi apparatus and the ribosomes.
[2 Marks]
Golgi apparatus :
repackage / transport, proteins; add carbohydrate group to protein.
Ribosomes :
Site of protein synthesis.
Explain how the structure of the sperm cell is specialised for carrying out its role.
[3 Marks]
A
Flagellum for movement;
Chromosomes / DNA, in haploid nucleus /AW, for fertilising egg cell; head / cap / acrosome,
Shaped for penetrating egg cell (membrane);
(Many) mitochondria for energy / ATP, for movement.
Explain the meaning of the term tissue.
[1 Mark]
Group of cells; of one or more types;
A ‘common origin’ with intercellular material/connective tissue / AW; (specialised) to perform particular function(s); R job
Name one example of a plant tissue.
[1 Mark]
xylem / phloem / epidermis / mesophyll / palisade / spongy mesophyll / chlorenchyma / etc./ meristem / cambium / suitable named tissue;
R leaf tissue / root tip / vascular tissue alone / xylem vessels / sieve tubes.
Show three ways in which prokaryotic and eukaryotic organisms differ in the structure of their cells.
[3 Marks]
Prokaryotic:
- no, nucleus / nucleolus / nuclear membrane / nuclear envelope
- circular DNA loop
- no, histones / (true) chromosome naked DNA
- no membrane-bound organelles/ cell wall
Eukaryotic:
- nucleus / nucleolus / nuclear membrane / nuclear envelope / DNA enclosed
- histones / chromosome DNA + protein
- membrane-bound organelles/ named e.g.
may have cell wall
State two features of root hair cells which adapt them for water uptake.
[2 Marks]
- large surface area (to volume) /
- low water potential; A ref to low solute potential (R refs to water concentration)
- A refs to (high) solute concentration thin wall /
- short diffusion path;
- uncutinised / permeable / unlignified / AW; rapid, growth / replacement.
Plants absorb water from the soil via their roots.
Describe the pathways and mechanisms by which water passes from the soil to the xylem vessels in the root.
[6 Marks]
- Osmosis in correct context; look for across membrane, or, into / out of, cell / root
- Moves down a water potential gradient / from high to low water potential; R along / across R concentration / diffusion gradients
- Most negative / lowest, in the xylem;
- (Uptake of) ions / minerals / solutes, into xylem / root hair; in context of WP gradient
- Tension in xylem / transpiration pull / cohesion-tension; relate to pathway in root
- (Moves) via the cell walls;
- (Moves) via, cytoplasm / vacuoles;
- Passage via the plasmodesmata; look for linking cytoplasm / through wall
- Casparian strip / suberin / waxy / fatty / AW, blocks, cell wall route / apoplast; A waterproof
- Water, crosses membrane / enters, cytoplasm / vacuole / symplast;
- AVP; e.g. pits in xylem / passage cells /aquaporins / protein channels / capillarity in cell wall (spaces
After water has entered the xylem vessels in the root, it passes through them to the rest of the plant.
Describe how two features of xylem vessels adapt them for water transport.
[4 Marks]
- Lignin / AW; (allows) adhesion / waterproof / stops collapse (under tension); A two functions
- rings / spirals / thickening / AW; A thick wall / rigid sides prevents collapse (under tension); R strong / support / stops bursting
- no cytoplasm / lack of contents / hollow / (empty) lumen / AW; R “dead” unqualified less resistance to flow / ease of flow / AW / more space (linked to lack of contents);
- lack of end walls / continuous tube; A long tube idea less resistance to flow / ease of flow; A continuous columns idea
- pits / pores, inside walls; A holes R gaps lateral movement / get round air bubbles / supplies(water) to cells or tissues / water in or out; R “just let things in and out” unqualified
- develop as a continuous water-filled column / AW; allows tension to pull water up / AW;
- narrow lumen / AW; idea of more capillary rise;
State the function of the mitochondria.
[2 Marks]
- Aerobic respiration; ATP production; provides ATP energy release; A provides energy (R produce / create / make / etc )
- AVP; e.g. Krebs cycle / regenerate NAD oxidative phosphorylation / protein synthesis / lipid synthesis/ oxidation of fats/ ornithine / urea, cycle
During phagocytosis, describe what happens within the vacuole after it fuses with the lysosome.
[4 Marks]
- enzymes / named enzymes / lysins; acid / low pH;
- digestion; A breaking down breaking , peptide / glycosidic / ester , bond; (R if in wrong context )
- hydrolysis;
- soluble / named, products.
State why squamous epithelium is described as a tissue.
[1 Mark]
- (made up of) one type of / (squamous) epithelium, cell(s).
- (group of) cells performing the same function(s); A task / job
State two features of a gas exchange surface, such as the lining of the alveolus.
[2 Marks]
- Large surface area;
- Permeable thin/short diffusion path;
- Moist;
- Good blood supply / close to blood;
- Well ventilated / in contact with respiratory medium;
Once in the red blood cells, the oxygen is picked up by haemoglobin. Explain how two features of red blood cells, other than the presence of haemoglobin, make them efficient in the collection of oxygen and its transport to the tissues.
[4 Marks]
- biconcave / AW; large surface area to volume (ratio); optimum oxygen uptake / fast diffusion; ora for oxygen release at tissues max 2 for this feature
- small / about 7µm (diameter) / about same size as capillary / AW; all haemoglobin close to surface / fast diffusion / short diffusion path / capillaries can be small to get close to all tissues / (RBC) close to capillary wall for exchange / AW;
- no nucleus / no or few organelles; maximum space for, oxygen carriage / haemoglobin;
- elastic / flexible / pliable , membrane; allows them to go along capillaries;
Various types of white blood cell can be found in the blood system. Some of these white blood cells are lymphocytes.
Describe one feature that would allow you to identify a white blood cell as a lymphocyte when viewed with a light microscope.
[1 Mark]
- Large nucleus
- Very little cytoplasm
- Non-granular cytoplasm
- About the same size as red blood cells but with a nucleus;
- A from a diagram R nucleus unqualified / bean-shaped nucleus / lobed nucleus.
State the word or phrase that best describes a structure made up of different types of tissue working together to perform a particular function.
[1 Mark]
Organ
