biology - key concepts 4
Call Kai
Learn
Practice Test
Spaced Repetition
Match
Flashcards
Knowt Play1/59
There's no tags or description
Looks like no tags are added yet.
Name | Mastery | Learn | Test | Matching | Spaced | Call with Kai |
|---|
No analytics yet
Send a link to your students to track their progress
60 Terms
Q: What is a eukaryotic cell?
A cell with a nucleus and membrane‑bound organelles (e.g. animal and plant cells).
Q: What is a prokaryotic cell?
A cell without a nucleus; DNA is free in the cytoplasm (e.g. bacteria).
Q: Function of the nucleus (animal & plant cells)?
Contains DNA coding for proteins; controls cell activities; enclosed by a nuclear membrane.
Q: Function of the cell membrane?
Controls what enters and leaves the cell.
Q: Function of cytoplasm?
Jelly‑like substance where chemical reactions occur; contains enzymes and organelles.
Q: Function of mitochondria?
Site of aerobic respiration; releases energy for the cell.
Q: Function of ribosomes?
Protein synthesis.
Q: Function of the plant cell wall?
Made of cellulose; provides strength and support.
Q: Function of chloroplasts?
Site of photosynthesis; contain chlorophyll to absorb light.
Q: Function of the permanent vacuole?
Contains cell sap; maintains turgor pressure and rigidity.
Q: What structures do bacterial cells have?
Cell membrane, cytoplasm, cell wall (peptidoglycan), ribosomes, circular chromosomal DNA, plasmids, flagella (some).
Q: Function of chromosomal DNA in bacteria?
Contains essential genetic information for the cell.
Q: What are plasmids?
Small rings of DNA carrying extra genes (e.g. antibiotic resistance).
Q: Function of flagella?
Movement.
Q: What is differentiation?
Process by which a cell develops specialised structures to perform a specific function.
Q: How is a sperm cell adapted to its function?
Long tail for movement; many mitochondria for energy; acrosome with enzymes to penetrate egg; haploid nucleus (23 chromosomes).
Q: How is an egg cell adapted to its function?
Large cytoplasm with nutrients; haploid nucleus; membrane changes after fertilisation to prevent more sperm entering.
Q: How are ciliated epithelial cells adapted?
Cilia beat to move mucus containing trapped bacteria to the stomach.
Q: How are root hair cells adapted?
Large surface area for absorption; large vacuole; many mitochondria for active transport of minerals.
Q: How are xylem cells adapted?
Dead, hollow tubes; lignin strengthens walls; transport water and mineral ions.
Q: How are phloem cells adapted?
Sieve plates allow flow of sugars; companion cells provide energy.
Q: What is magnification?
How many times larger the image is than the real object.
Q: Maximum magnification and resolution of a light microscope?
~2000× magnification; ~200 nm resolution.
Q: Why are electron microscopes more powerful?
Electrons have a shorter wavelength than light, giving higher resolution.
Q: SEM vs TEM?
SEM produces 3D surface images; TEM produces 2D images of internal structures.
Q: How has electron microscopy increased understanding?
Allowed clearer viewing of organelles and discovery of very small structures like viruses and ribosomes.
Q: Formula for magnification calculations?
Magnification = image size ÷ actual size.
Q: When should estimations be used?
When counting everything is impractical; use samples to estimate totals.
Q: Metric prefixes used in biology?
milli (10⁻³), micro (10⁻⁶), nano (10⁻⁹), pico (10⁻¹²).
Q: What is standard form?
Writing numbers as A × 10ⁿ where 1 ≤ A < 10.
Q: Steps to use a light microscope?
Place slide; start on lowest magnification; focus; increase magnification and refocus.
Q: Why are stains used?
To make structures easier to see.
Q: What must scientific drawings include?
Clear outlines, no shading, labels, title, magnification or scale bar.
Q: What is an enzyme?
A biological catalyst that speeds up reactions without being used up.
Q: What is the active site?
Region of the enzyme where the substrate binds.
Q: What is enzyme specificity?
Each enzyme only works with a specific substrate.
Q: Explain the lock‑and‑key model.
Substrate fits the active site; enzyme‑substrate complex forms; products released.
Q: What is denaturation?
Permanent change in enzyme shape so the active site no longer fits the substrate.
Q: Effect of temperature on enzymes?
Rate increases to optimum; above optimum enzymes denature.
Q: Effect of pH on enzymes?
Each enzyme has an optimum pH; extremes denature enzymes.
Q: Effect of substrate concentration?
Rate increases until enzymes are saturated.
Q: What enzyme is used and what does it break down?
Amylase; breaks starch into maltose.
Q: How is starch detected?
Iodine turns blue‑black if starch is present.
Q: What does the shortest reaction time show?
The optimum pH.
Q: Formula for rate of reaction?
Rate = change ÷ time.
Q: What do carbohydrases do?
Break carbohydrates into sugars (e.g. amylase).
Q: What do proteases do?
Break proteins into amino acids (e.g. pepsin).
Q: What do lipases do?
Break lipids into fatty acids and glycerol.
Q: Test for starch?
Iodine → orange to blue‑black.
Q: Test for reducing sugars?
Benedict’s + heat → blue to brick‑red.
Q: Test for protein?
Biuret → blue to purple.
Q: Test for lipids?
Emulsion test → white layer.
Q: What does calorimetry measure?
Energy content of food.
Q: What is diffusion?
Passive movement from high to low concentration.
Q: What is osmosis?
Diffusion of water across a partially permeable membrane from dilute to concentrated solution.
Q: What is active transport?
Movement against a concentration gradient using energy (ATP).
Q: Independent variable?
Sucrose concentration.
Q: Dependent variable?
Change in mass of potato.
Q: Percentage change formula?
(Change in mass ÷ original mass) × 100.