BIOLOGY ALL- AQSA YEAR 9 EXAM
QUESTIONS WITH VERIFIED ANSWERS
2024-2025
2.1 describe the levels of organisation in organisms: organelles, cells, tissues,
organs and systems - ANSWER Tissues
are a collection of similar cells all serving a common function.
Organs
are made up of several kinds of tissues together forming a functioning unit.
Systems
are several organs forming an organ system. Like the cardiovascular system is
made up of the heart, blood and blood vessels.
2.2 describe cell structures, including the nucleus, cytoplasm, cell membrane, cell
wall, mitochondria, chloroplasts, ribosomes and vacuole - ANSWER NUCLEUS
Membrane-bound organelle that contains genetic material
CYTOPLASM
Material that fills cell to facilitate chemical reactions and hold organelles in place
CELL MEMBRANE
Phospholipid bilayer that controls the movement of substances into and out of cell
CELL WALL
External to cell membrane that protects and maintains the shape of cell (prevents
cell from bursting)
,MITOCHONDRIA
Membrane-bound organelle that carries out cellular respiration
CHLOROPLAST
Plastid in plants that carries out photosynthesis
RIBOSOME
Site of protein synthesis
VACUOLE
Storage organelle in plants to store Water and dissolved substances
2.3 describe the functions of the nucleus, cytoplasm, cell membrane, cell wall,
mitochondria, chloroplasts, ribosomes and vacuole - ANSWER NUCLEUS
Membrane-bound organelle that contains genetic material
CYTOPLASM
Material that fills cell to facilitate chemical reactions and hold organelles in place
CELL MEMBRANE
Phospholipid bilayer that controls the movement of substances into and out of cell
CELL WALL
External to cell membrane that protects and maintains the shape of cell (prevents
cell from bursting)
MITOCHONDRIA
Membrane-bound organelle that carries out cellular respiration
CHLOROPLAST
Plastid in plants that carries out photosynthesis
RIBOSOME
,Site of protein synthesis
VACUOLE
Storage organelle in plants to store Water and dissolved substances
2.4 know the similarities and differences in the structure of plant and animal cells -
ANSWER Plant cell: Fixed shape, large vacuole, cell wall, chloroplast
Animal cell: No fixed shape, little or no vacuole, no cell wall, no chloroplast
2.7 identify the chemical elements present in carbohydrates, proteins and lipids
(fats and oils) - ANSWER CARBOHYDRATE
CHO
LIPIDS
CHO
PROTEINS
CHON
2.8 describe the structure of carbohydrates, proteins and lipids as large molecules
made up from smaller basic units: starch and glycogen from simple sugars, protein
from amino acids, and lipid from fatty acids and glycerol - ANSWER STARCH
AND GLYCOGEN
Composed of simple sugars
PROTEIN
, Composed of amino acids
LIPID
Composed of fatty acids and glycerol
CARBOHYDRATES
Saccharide unit (sugars)
2.9 practical: investigate food samples for the presence of glucose, starch, protein
and fat - ANSWER Glucose: Benedicts solution
Place two spatulas of the food sample into a test tube or 1 cm3 if the sample is
liquid. Add about 1 cm3 depth of water to the tube and stir to mix.
Add an equal volume of Benedict's solution and mix.
Place the tube in a water bath at about 95°C for a few minutes.
Record the colour of the solution.
Benedict's solution gradually turns from blue to cloudy orange or brick red when
heated with a reducing sugar. Sucrose is a non-reducing sugar and does not react
with Benedict's solution
Starch: Iodine test
Place one spatula of the food sample on a dish or 1 cm3 if the sample is liquid.
Using a dropper, place a few drops of iodine solution onto the food.
Record any change in the colour of the solution.
Starch is detected using iodine solution. This turns blue-black in the presence of
starch.
Protein: Biuret solution
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