Flashcards · 0610 · Topic 2

Organisation of the organism flashcards

13 cards on Topic 2, subtopics 2.1 to 2.2. Pick a subtopic or study them all.

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Three structures in a plant cell but not in an animal cell: Cell wall, chloroplasts, large permanent vacuole.
What does a bacterial cell have that plant and animal cells do not?: Circular DNA (no true nucleus) and plasmids. Bacteria also have no mitochondria or chloroplasts.
Functions of the nucleus, cell membrane, mitochondria and ribosomes: Nucleus: contains DNA, controls the cell. Membrane: controls what enters and leaves. Mitochondria: aerobic respiration releases energy. Ribosomes: make proteins.
Specialised cells: ciliated cell, root hair cell, palisade mesophyll cell: Ciliated cell: movement of mucus in the trachea and bronchi. Root hair cell: absorption. Palisade mesophyll cell: photosynthesis.
Specialised cells: neurone, red blood cell, sperm and egg cells: Neurone: conduction of electrical impulses. Red blood cell: transport of oxygen. Sperm and egg cells (gametes): reproduction.
Tissue, organ and organ system: Tissue: a group of cells with similar structures working together to perform a shared function. Organ: several tissues working together. Organ system: a group of organs with related functions working together.
Levels of organisation, smallest to largest: Cell → tissue → organ → organ system → organism.

Magnification formula: magnification = image size ÷ actual size (both in the same units).
A drawing is 45 mm across; the actual cell is 0.03 mm. Magnification?: 45 ÷ 0.03 = ×1500.
How do you find the actual size of a specimen from a drawing?: actual size = image size ÷ magnification.
The most common way marks are lost in magnification calculations: Mixing units, e.g. an image measured in mm with an actual size in μm. Convert both to the same unit first.
Millimetres and micrometresExtended: 1 mm = 1000 μm. To change μm to mm divide by 1000; to change mm to μm multiply by 1000.
A cell 0.02 mm across gives a 60 mm image. Magnification, and the cell size in μm?Extended: 60 ÷ 0.02 = ×3000. 0.02 mm × 1000 = 20 μm.