Structure & Function of Plant Cells Flashcards
What three features are unique to plant cells (compared to animal cells)?
- Cell wall.
- Plastids.
- Vacuole.
The cell wall maintains and determines the …….. of the cell and controls the rate and direction of ………… . It envelopes the whole cell - …………. of the …………. membrane to protect against …………. and environmental changes. The cell wall also maintains …………. pressure.
Shape, growth, plasma, pathogens, turgor.
How many cells walls are there between adjoining plant cells?
Two. Each plant cell has its own cell wall. Cell-to-cell interactions take place through the walls.
What are the three layers of the plant cell wall (from the outside in)?
- Middle lamella: the gap between plant cell walls.
- Primary cell wall.
- Plasma membrane.
Which material, which gives plant cell walls their strength as it is arranged in rod-like criss-crossed microfibrils, is one of the earth’s most abundant?
Cellulose.
Which material cross-links cellulose microfibrils in plant cells walls?
Hint: it is important in jam-making!
Pectin.
What is a simpler, shorter form of cellulose?
Hemicellulose.
Outline the processes in the plant cell wall when they need to grow.
Cell wall enzymes loosen the cross-linkages between the microfibrils to allow the cell wall to expand. New material is deposited into the cell wall.
When is the secondary cell wall deposited between the primary cell wall and the plasma membrane? What is its function?
The secondary cell wall is deposited when the cell has stopped growing. It fixes the final cell shape and gives it support, strength and protection.
The secondary cell wall can be made of a number of materials. Give some examples.
Cutin, lignin, cellulose, suberin.
What is anther dehissence?
There is a secondary thickening of the endodermis layer in the anther. This causes pressure to buildup inside the anther, and the anther bursts open, dispersing pollen.
Plants can shed organs by developing a protective layer around the plant cell and cells of the organ being removed. The middle lamella between the two cell walls is digested so the unwanted organ is removed. What is the name of this process?
Abscission.
True or false? Plant cells have lysosomes, centrioles and flagella, in common with most eukaryotes.
False. Plant cells do not have lysosomes, centrioles or flagella (except for come plant sperm).
Chloroplasts are an example of a plastid. Name some others and their functions.
- Chromoplasts: pigment synthesis and storage.
- Leucoplasts: storage of energy sources.
- Elaioplasts: lipid storage, found in plant seeds.
- Proteinoplasts: protein storage.
- Amyloplasts: starch storage and synthesis.
- Statoliths: sense gravity and controls direction of growth.
What is synthesised in chloroplasts?
Protein. Chloroplasts contain their own genetic material and machinery for this.
Grana are formed of stacked membranes called…?
Thylakoids.
What is the name of the internal fluid of chloroplasts? What happens there?
Stroma. It is a soluble matrix where carbon dioxide fixation takes place.
Fill in the blanks:
The …………. is a membrane-bound organelle filled with sap. It may comprise the ………… of a cell’s volume. The fluid in the ………… is often at an acidic pH, which can affect ……….. in the plant.
Vacuole, majority, vacuole, pigmentation.
What are the roles of the vacuole?
- General cell homeostasis.
- Maintaining turgor pressure (if this pressure is lost, the cytoplasm shrinks away from the cell wall and the plant wilts!).
- Detoxification. Toxins can be ‘dumped’ into the vacuole.
- Storage tissues.
What is the difference between the embryos of a monocot and a dicot? How can this difference be seen in seedlings?
Monocots have one cotyledon, so one seedling leaf is generated. Dicots have two cotyledons, so two seedling leavea are generated.
Monocot or dicot?
1. Parallel veins.
2. Netlike veins.
Monocot: parallel veins.
Dicot: netlike veins.
