Topic 1 : Key Concepts in Biology Flashcards
What does the nucleus do in animal and plant cells?
It contains DNA and controls the activities of the cell.
What is the function of the cell membrane in animal and plant cells?
It controls what enters and leaves the cell.
What is the role of mitochondria?
They are the site of aerobic respiration, releasing energy.
What do ribosomes do?
They are the site of protein synthesis.
What additional structures do plant cells have that animal cells do not?
Cell wall, chloroplasts, and a permanent vacuole.
What is the function of the chloroplasts in plant cells?
They absorb light energy for photosynthesis.
What is the role of the cell wall in plant cells?
It provides support and strengthens the cell.
What does the vacuole contain and what is its function?
It contains cell sap and helps keep the cell turgid.
What are the main structures found in a bacterial cell?
Chromosomal DNA, plasmid DNA, cell membrane, ribosomes, and flagella.
What is the function of chromosomal DNA in bacteria?
It contains the genetic information, not enclosed in a nucleus.
What is the role of plasmid DNA in bacteria?
It carries extra genes that may help survival (e.g., antibiotic resistance).
What is the function of flagella in bacteria?
It helps the cell move.
How is a sperm cell adapted to its function?
It has a tail for swimming, a mitochondria-rich middle for energy, an acrosome with enzymes to digest the egg’s membrane, and a haploid nucleus.
How is an egg cell adapted to its function?
It has nutrients in the cytoplasm, a haploid nucleus, and its membrane changes after fertilisation to stop more sperm entering.
How are ciliated epithelial cells adapted?
They have hair-like structures (cilia) to move mucus and trapped particles out of the lungs or oviduct.
How has microscope technology helped us understand cells better?
Electron microscopes provide higher resolution and magnification, allowing us to see smaller structures more clearly.
How do you calculate magnification?
Magnification = image size ÷ actual size.
What are the prefixes for different cell measurements?
Milli = 10⁻³, Micro = 10⁻⁶, Nano = 10⁻⁹, Pico = 10⁻¹².
How can standard form help with cell size calculations?
It makes very large or small numbers easier to work with (e.g., 0.000001 = 1 × 10⁻⁶).
What is a key rule when drawing scientific diagrams of cells?
Draw with clear lines, no shading, label neatly and accurately.
What is the active site of an enzyme?
The region where a specific substrate binds to the enzyme.
Why are enzymes specific?
The shape of the active site only fits one type of substrate (like a lock and key).
What does it mean when an enzyme is denatured?
Its active site changes shape and can no longer bind to the substrate.
How does temperature affect enzyme activity?
Higher temperatures increase activity until the enzyme denatures at too high a temperature.
