For Class 8, 9 & 10
Master the basics - and everything after gets easier
Concept-first questions with clear model answers in Physics, Chemistry, Maths and Biology, all NCERT-aligned. Start early, build the habit, and walk into your boards, NEET and JEE already ahead.
Interactive lessons
learn by playingDrag, slide and build - watch each concept come alive, then reveal the answer.
200 interactive lessons
Ohm's law
Class 10 Physics
Slide V & R, watch the bulb glow
Open →pH scale
Class 10 Chemistry
Slide across acids and bases
Open →Atomic number and mass number
Class 9 Chemistry
Add protons & neutrons, build shells
Open →Laws of reflection
Class 8 Physics
Change the angle, watch it bounce
Open →Volume of a sphere
Class 9 Maths
Grow the radius, see the volume
Open →Area of a trapezium
Class 8 Maths
Drag the sides, read the area
Open →Power of a lens
Class 10 Physics
Move the object, trace the rays
Open →Food chain and energy flow
Class 10 Biology
Follow the energy as it flows
Open →Speed
Class 8 Physics
Slide distance & time, watch the speed
Open →Density
Class 9 Physics
Pack mass into volume, float or sink
Open →Work done
Class 9 Physics
Push harder or farther, watch work grow
Open →Kinetic energy
Class 9 Physics
Speed it up - energy grows with the square
Open →Power of a lens
Class 10 Physics
Shorten the focal length, boost the power
Open →Mole concept
Class 9 Chemistry
Weigh out grams, count the moles
Open →Avogadro's number
Class 9 Chemistry
Add moles, count the particles
Open →Microscope magnification
Class 8 Biology
Grow the image, read the magnification
Open →Population density
Class 10 Biology
Add individuals, shrink the land, see crowding
Open →Simple interest
Class 8 Maths
Slide money, rate & time, watch interest
Open →Pythagoras theorem
Class 9 Maths
Stretch the two sides, get the hypotenuse
Open →Probability of an event
Class 10 Maths
Change the outcomes, watch the odds
Open →Newton's second law
Class 9 Physics
Push a mass, pick an acceleration
Open →Momentum
Class 9 Physics
Slide mass & velocity, build momentum
Open →Pressure
Class 8 Physics
Shrink the area, feel the pressure rise
Open →Weight
Class 9 Physics
Change the planet's gravity, watch your weight
Open →Refractive index
Class 10 Physics
Slow light in the medium, raise the index
Open →Resistors in series
Class 10 Physics
Add two resistors in a line
Open →Mass percentage of a solution
Class 9 Chemistry
Dissolve solute, read the strength
Open →Concentration of a solution
Class 9 Chemistry
Pack solute into less liquid
Open →Population change
Class 10 Biology
Balance births against deaths
Open →Compound microscope
Class 8 Biology
Combine eyepiece & objective lenses
Open →Area of a circle
Class 8 Maths
Grow the radius, watch the area square
Open →Volume of a cuboid
Class 8 Maths
Stretch length, breadth & height
Open →Electronic configuration and valency
Class 9 Chemistry
Slide the atomic number, build the atom
Open →Homologous series (alkanes)
Class 10 Chemistry
Add carbons, name the compound
Open →Mass number
Class 9 Chemistry
Add protons & neutrons, get the mass number
Open →Power
Class 9 Physics
More work in less time = more power
Open →Potential energy
Class 9 Physics
Lift a mass higher, store energy
Open →Wave speed
Class 9 Physics
Tune frequency & wavelength, set the speed
Open →Electric current
Class 10 Physics
Push charge per second, get the current
Open →Percentage
Class 8 Maths
Compare part to whole as a %
Open →Electron dot structure
Class 9 Chemistry
Draw valence electrons as dots
Open →Acceleration
Class 9 Physics
Speed up over time, find acceleration
Open →Distance, speed and time
Class 8 Physics
Set speed & time, cover the distance
Open →Frequency and time period
Class 9 Physics
Shorten the period, raise the frequency
Open →Heating effect of current
Class 10 Physics
Raise the current, watch heating soar
Open →Area of a triangle
Class 8 Maths
Set base & height, halve the rectangle
Open →Area of a rectangle
Class 8 Maths
Set length & breadth, fill the area
Open →Mean (average)
Class 9 Maths
Share the total equally across items
Open →Discount
Class 8 Maths
Slide price & % off, see the saving
Open →Heart rate
Class 10 Biology
Set heart rate & time, count the beats
Open →Resistors in parallel
Class 10 Physics
Wire two resistors side by side
Open →Electric charge
Class 10 Physics
Flow current over time, collect charge
Open →Electrical energy and units
Class 10 Physics
Run appliances, add up the units
Open →Kelvin temperature scale
Class 9 Chemistry
Slide Celsius, read the Kelvin
Open →Moles from number of particles
Class 9 Chemistry
Divide particles by Avogadro's number
Open →Ten percent law
Class 10 Biology
See 10% of energy reach the next level
Open →Area of a square
Class 8 Maths
Grow the side, square the area
Open →Volume of a cube
Class 8 Maths
Grow the edge, cube the volume
Open →Circumference of a circle
Class 8 Maths
Grow the radius, roll out the rim
Open →Surface area of a cube
Class 9 Maths
Grow the edge, cover six faces
Open →Potential difference
Class 10 Physics
Share work across charge, get volts
Open →Resistance from Ohm's law
Class 10 Physics
Divide voltage by current, get resistance
Open →Echo and SONAR
Class 9 Physics
Time the echo, find the distance
Open →Mass from moles
Class 9 Chemistry
Multiply moles by molar mass
Open →Breathing rate
Class 10 Biology
Set breathing rate & time
Open →Volume of a cylinder
Class 10 Maths
Set radius & height, fill the can
Open →Compound interest
Class 8 Maths
Compound money over years
Open →Profit and loss percentage
Class 8 Maths
Set cost & selling price, see profit %
Open →Perimeter of a rectangle
Class 8 Maths
Set length & breadth, walk the border
Open →Surface area of a sphere
Class 10 Maths
Grow the radius, wrap the ball
Open →Time period
Class 9 Physics
Raise the frequency, shrink the period
Open →Relative velocity
Class 9 Physics
Two objects approach - add their speeds
Open →Average velocity
Class 9 Physics
Average the start and end speeds
Open →Equations of motion (v = u + at)
Class 9 Physics
Accelerate from u for a time t
Open →Kelvin to Celsius
Class 9 Chemistry
Slide Kelvin, read the Celsius
Open →Population growth rate
Class 10 Biology
Balance births vs deaths per population
Open →Perimeter of a square
Class 8 Maths
Grow the side, walk four edges
Open →Perimeter of a triangle
Class 8 Maths
Add the three sides
Open →Area of a parallelogram
Class 8 Maths
Set base & height, slide the shape
Open →Area of a rhombus
Class 8 Maths
Set the two diagonals
Open →Equations of motion (distance)
Class 9 Physics
Start, accelerate, cover ground
Open →Joule's law of heating
Class 10 Physics
Raise current, resistance or time
Open →Electric power (P = VI)
Class 10 Physics
Multiply voltage by current
Open →Average atomic mass of isotopes
Class 9 Chemistry
Mix two isotopes by abundance
Open →Seed germination percentage
Class 9 Biology
Count sprouted seeds out of the total
Open →Volume of a cone
Class 9 Maths
Set radius & height, fill the cone
Open →Surface area of a cylinder
Class 9 Maths
Wrap the side and both ends
Open →Surface area of a cuboid
Class 9 Maths
Cover all six rectangular faces
Open →nth term of an AP
Class 10 Maths
Step from the first term by d
Open →Sum of an AP
Class 10 Maths
Add up the first n terms
Open →Focal length of a mirror
Class 10 Physics
Halve the radius to find the focus
Open →Speed of light in a medium
Class 10 Physics
Raise the index, slow the light
Open →Percentage purity
Class 9 Chemistry
Weigh the pure part of a sample
Open →Slope of a line
Class 10 Maths
Rise over run gives the steepness
Open →Percentage change
Class 8 Maths
Compare a new value to the old
Open →Volume of a hemisphere
Class 9 Maths
Grow the radius of half a ball
Open →Area of a sector
Class 10 Maths
Cut a slice of angle from a circle
Open →Length of an arc
Class 10 Maths
Measure the curved edge of a slice
Open →Slant height of a cone
Class 9 Maths
Combine radius & height for the slant
Open →Unit conversion (km/h to m/s)
Class 9 Physics
Convert km/h into m/s
Open →Equations of motion (v^2 = u^2 + 2as)
Class 9 Physics
Accelerate over a distance, find v
Open →Impulse
Class 9 Physics
Hit harder or longer, change momentum
Open →Wavelength
Class 9 Physics
Speed over frequency gives wavelength
Open →Oscillations
Class 9 Physics
Vibrate at a frequency for a time
Open →Cost of electricity
Class 10 Physics
Units times rate gives the bill
Open →Number of neutrons
Class 9 Chemistry
Take protons away from the mass number
Open →Curved surface area of a cone
Class 9 Maths
Wrap the slanted side of a cone
Open →Total surface area of a cone
Class 9 Maths
Add the base circle to the cone's side
Open →Curved surface area of a hemisphere
Class 9 Maths
Cover the dome of a hemisphere
Open →Diagonal of a square
Class 9 Maths
Cross a square corner to corner
Open →Unit conversion (m/s to km/h)
Class 9 Physics
Convert m/s into km/h
Open →Distance from velocities
Class 9 Physics
From two speeds, find the distance
Open →Diagonal of a rectangle
Class 9 Maths
Cross a rectangle corner to corner
Open →Diagonal of a cuboid
Class 9 Maths
The longest rod that fits in a box
Open →Area by Heron's formula
Class 9 Maths
Area from just the three sides
Open →Interior angle sum of a polygon
Class 8 Maths
Add up a polygon's inside angles
Open →Exterior angle of a regular polygon
Class 8 Maths
Share 360 among a polygon's corners
Open →Number of diagonals of a polygon
Class 8 Maths
Count the diagonals of a polygon
Open →Discriminant
Class 10 Maths
Test how many roots a quadratic has
Open →Sum of roots
Class 10 Maths
Sum of a quadratic's roots
Open →Punnett square (monohybrid cross)
Class 10 Biology
Cross two parents, predict the offspring
Open →Balancing chemical equations
Class 10 Chemistry
Slide coefficients until atoms balance
Open →Writing chemical formulae (valency)
Class 9 Chemistry
Criss-cross valencies into a formula
Open →Current from power
Class 10 Physics
Divide power by voltage for current
Open →Power (P = V^2 / R)
Class 10 Physics
Voltage squared over resistance
Open →Sine ratio
Class 10 Maths
Opposite over hypotenuse
Open →Cosine ratio
Class 10 Maths
Adjacent over hypotenuse
Open →Tangent ratio
Class 10 Maths
Opposite over adjacent
Open →Area of an equilateral triangle
Class 9 Maths
Area of an equilateral triangle
Open →Curved surface area of a cylinder
Class 9 Maths
Wrap only the curved side
Open →Loss percentage
Class 8 Maths
Sell below cost, find the loss %
Open →Amount with simple interest
Class 8 Maths
Principal plus its simple interest
Open →Distance formula
Class 10 Maths
Straight distance between two points
Open →States of matter
Class 9 Chemistry
Heat particles solid → liquid → gas
Open →Parts of a plant cell
Class 8 Biology
Tap a cell part to see its job
Open →Diagonal of a cube
Class 9 Maths
Longest diagonal through a cube
Open →Total surface area of a hemisphere
Class 9 Maths
Dome plus its flat circle
Open →Sum of first n natural numbers
Class 10 Maths
Add 1 + 2 + ... + n instantly
Open →Range of data
Class 9 Maths
Spread from smallest to largest
Open →Class mark
Class 9 Maths
Midpoint of a class interval
Open →Selling price from profit percent
Class 8 Maths
Mark up cost by a profit %
Open →Perimeter of a sector
Class 10 Maths
Two radii plus the curved arc
Open →Circumference from diameter
Class 8 Maths
Circumference straight from diameter
Open →Power (P = F x v)
Class 9 Physics
Force times velocity gives power
Open →Percentage of a number
Class 8 Maths
Find a percentage of a number
Open →Series and parallel circuits
Class 10 Physics
Break a bulb in series vs parallel
Open →Symbols of elements
Class 9 Chemistry
Match each element to its symbol
Open →Free fall (velocity)
Class 9 Physics
Drop from a height, hit this speed
Open →Free fall (time)
Class 9 Physics
How long a drop takes
Open →Free fall (distance)
Class 9 Physics
Distance fallen in a given time
Open →Complement of an event
Class 10 Maths
Chance an event does NOT happen
Open →Product of roots
Class 10 Maths
Product of a quadratic's roots
Open →Exterior angle theorem
Class 9 Maths
Exterior angle = sum of remote interiors
Open →Complementary angles
Class 10 Maths
What adds to 90 degrees
Open →Supplementary angles
Class 9 Maths
What adds to 180 degrees
Open →Perimeter of a semicircle
Class 10 Maths
Curved half plus the diameter
Open →Area of a semicircle
Class 10 Maths
Half the area of a circle
Open →Turning effect (moments)
Class 9 Physics
Balance the see-saw with moments
Open →Reflex arc
Class 10 Biology
Step through a reflex, stimulus to action
Open →Buoyant force (upthrust)
Class 9 Physics
Displace liquid, feel the upthrust
Open →Relative density
Class 9 Physics
Compare a density to water's
Open →Power in lifting a load
Class 9 Physics
Lift a load, faster needs more power
Open →Cosecant ratio
Class 10 Maths
Hypotenuse over opposite
Open →Secant ratio
Class 10 Maths
Hypotenuse over adjacent
Open →Cotangent ratio
Class 10 Maths
Adjacent over opposite
Open →Height from angle of elevation
Class 10 Maths
Height from an angle of elevation
Open →Area of a quadrant
Class 10 Maths
A quarter of a circle's area
Open →Interior angle of a regular polygon
Class 8 Maths
One inside angle of a regular polygon
Open →Sum of first n odd numbers
Class 10 Maths
Add the first n odd numbers
Open →Sum of first n even numbers
Class 10 Maths
Add the first n even numbers
Open →Quadratic formula (a root)
Class 10 Maths
Larger root of a quadratic
Open →LCM from HCF
Class 10 Maths
LCM from the product and HCF
Open →Depreciation
Class 8 Maths
Value drops by a % each year
Open →Cost price from selling price
Class 8 Maths
Work back to the cost price
Open →Downstream speed
Class 8 Maths
Row with the current
Open →Upstream speed
Class 8 Maths
Row against the current
Open →Average speed for a round trip
Class 8 Maths
Average speed there and back
Open →Sales tax / GST
Class 8 Maths
Tax added on a price
Open →Area of a ring (annulus)
Class 10 Maths
Area of a ring between two circles
Open →Edge of a cube from volume
Class 9 Maths
Edge back from the volume
Open →Radius from area
Class 10 Maths
Radius back from a circle's area
Open →Side from area of a square
Class 8 Maths
Side back from a square's area
Open →Height of a triangle from area
Class 9 Maths
Height back from area and base
Open →Rate from simple interest
Class 8 Maths
Rate back from the interest
Open →Time from simple interest
Class 8 Maths
Time back from the interest
Open →Principal from simple interest
Class 8 Maths
Principal back from the interest
Open →Mean proportional
Class 10 Maths
Geometric mean of two numbers
Open →Fourth proportional
Class 8 Maths
Complete the proportion a : b = c : ?
Open →Marked price from selling price
Class 8 Maths
Marked price back from the sale price
Open →Chambers of the human heart
Class 10 Biology
Tap a heart chamber to see its job
Open →Equation of a line (y = mx + c)
Class 9 Maths
Read y off a straight line
Open →Average term of an AP
Class 10 Maths
Average of first and last term
Open →Number of terms in an AP
Class 10 Maths
How many terms in an AP
Open →Midpoint of two points
Class 10 Maths
x-coordinate of a midpoint
Open →Empirical mode
Class 10 Maths
Estimate the mode from mean & median
Open →Length of a shadow
Class 10 Maths
Shadow from height and sun angle
Open →Train crossing a pole
Class 8 Maths
Speed to cross a pole
Open →Time and work
Class 8 Maths
More workers, fewer days
Open →Dividing in a ratio
Class 8 Maths
Split a total in a ratio
Open →Unitary method
Class 8 Maths
Cost of a single item
Open →Your progress — Foundation - Class 8 to 10
0 / 586 learnedTap “Mark as learned” on a card as you master it — saved on this device, no sign-in needed.
Your badges
0/12 earned
Showing 11 questions for Class 9. Tap a card to reveal the answer.
BiologyThe Fundamental Unit of LifemediumGive two differences between a prokaryotic and a eukaryotic cell.
Reveal answer ↓
What it is
Prokaryotes (bacteria) have no true nucleus; eukaryotes (plants, animals) have a nucleus and organelles.
Answer
A prokaryotic cell has no true nucleus - its genetic material lies free in the cytoplasm - and it lacks membrane-bound organelles like mitochondria; bacteria are examples. A eukaryotic cell has a true, membrane-bound nucleus and membrane-bound organelles; plant and animal cells are examples. Eukaryotic cells are usually larger and more complex.
- •Prokaryote: no true nucleus, no membrane-bound organelles (bacteria)
- •Eukaryote: true nucleus + organelles (plants, animals)
- •Eukaryotic cells are larger and more complex
Why learn this
It's the deepest divide in the living world and why antibiotics can hit bacteria but not your own cells.
💡 Memory trick
PRO = primitive, NO true nucleus; EU = 'true', good nucleus.
BiologyThe Fundamental Unit of LifemediumWhat is osmosis? What happens to a cell placed in pure water?
Reveal answer ↓
What it is
Osmosis is water moving across a membrane to balance the concentration on both sides.
Answer
Osmosis is the movement of water molecules through a selectively permeable membrane from a region of higher water concentration to a region of lower water concentration. A cell placed in pure water (a hypotonic solution) gains water by osmosis and swells; an animal cell may even burst, while a plant cell becomes firm (turgid) because of its cell wall.
- •Water moves across a selectively permeable membrane
- •From higher to lower water concentration
- •In pure water a cell swells (animal may burst; plant turns turgid)
Why learn this
It's how roots absorb water, how our cells stay hydrated and why salt preserves food.
💡 Memory trick
Water follows the salt. Cell in pure water swells; in salty water it shrinks.
BiologyThe Fundamental Unit of LifemediumGive three differences between prokaryotic and eukaryotic cells.
Reveal answer ↓
What it is
Prokaryotic cells lack a true nucleus and membrane-bound organelles; eukaryotic cells have both.
Answer
A prokaryotic cell has no true, membrane-bound nucleus - its genetic material lies free in the cytoplasm as a nucleoid - while a eukaryotic cell has a well-defined nucleus surrounded by a nuclear membrane. Prokaryotic cells lack membrane-bound organelles such as mitochondria, whereas eukaryotic cells possess them. Prokaryotic cells are generally smaller and simpler, for example bacteria, while eukaryotic cells are larger, for example plant and animal cells.
- •Prokaryote: no true nucleus (nucleoid)
- •Eukaryote: true, membrane-bound nucleus
- •Prokaryotes lack membrane-bound organelles
- •Bacteria vs plant/animal cells
Why learn this
It is the most basic division of all cellular life.
💡 Memory trick
Pro = 'primitive', no true nucleus (bacteria). Eu = 'true' nucleus (plants, animals).
BiologyThe Fundamental Unit of LifemediumWhat is the plasma membrane? Define diffusion.
Reveal answer ↓
What it is
The plasma membrane is a selectively permeable boundary that controls what enters and leaves the cell; diffusion moves substances from high to low concentration.
Answer
The plasma membrane, or cell membrane, is the outermost living covering of a cell that separates its contents from the surroundings. It is selectively permeable, meaning it allows only certain substances to pass through it. Diffusion is the movement of particles of a substance from a region of higher concentration to a region of lower concentration; gases such as carbon dioxide and oxygen move in and out of the cell by diffusion.
- •Plasma membrane: outer living boundary
- •Selectively permeable
- •Diffusion: high to low concentration
- •Gases exchanged by diffusion
Why learn this
It keeps useful substances in and wastes moving out, keeping the cell alive.
💡 Memory trick
Selectively permeable = it lets only some substances pass. Diffusion = high to low concentration.
BiologyThe Fundamental Unit of LifehardDefine osmosis. What happens to a cell placed in a hypotonic and in a hypertonic solution?
Reveal answer ↓
What it is
Osmosis is the movement of water molecules through a selectively permeable membrane from a dilute to a concentrated solution.
Answer
Osmosis is the movement of water molecules from a region of higher water concentration (dilute solution) to a region of lower water concentration (concentrated solution) through a selectively permeable membrane. When a cell is placed in a hypotonic solution (more dilute than the cell), water enters and the cell swells. When placed in a hypertonic solution (more concentrated than the cell), water leaves and the cell shrinks (in plant cells this is plasmolysis). In an isotonic solution there is no net movement of water.
- •Osmosis: water through a selectively permeable membrane
- •Dilute to concentrated (of solute)
- •Hypotonic: cell swells
- •Hypertonic: cell shrinks (plasmolysis)
Why learn this
It explains how roots absorb water and how cells swell or shrink.
💡 Memory trick
Osmosis = water moves to where there is MORE solute (to dilute it).
BiologyThe Fundamental Unit of LifemediumWhat is the cell wall made of? Define plasmolysis.
Reveal answer ↓
What it is
The cell wall is a rigid outer covering of plant cells made of cellulose; plasmolysis is the shrinking of the cell contents in a hypertonic solution.
Answer
The cell wall is the tough, rigid, non-living outer covering found in plant cells, mainly made of a carbohydrate called cellulose. It gives the cell shape, strength and protection. Plasmolysis is the process in which a plant cell placed in a highly concentrated (hypertonic) solution loses water by osmosis, so its cytoplasm and cell membrane shrink and pull away from the cell wall.
- •Cell wall: rigid, made of cellulose (plant cells)
- •Gives shape and support
- •Plasmolysis: cell shrinks in a hypertonic solution
- •Protoplasm pulls away from the wall
Why learn this
The cell wall gives plants strength, and plasmolysis shows the membrane is selectively permeable.
💡 Memory trick
Cell wall = cellulose armour of plant cells. Plasmolysis = protoplasm pulls away from the wall.
BiologyThe Fundamental Unit of LifeeasyState the functions of the nucleus.
Reveal answer ↓
What it is
The nucleus is the control centre of the cell and contains the genetic material (DNA) in chromosomes.
Answer
The nucleus is a large, spherical organelle bounded by a nuclear membrane. It contains the chromosomes, which carry the genetic material DNA in the form of genes. The nucleus controls all the activities of the cell, so it is called the control centre or brain of the cell. It also plays a central role in cell reproduction (cell division) and in the inheritance of characters from parents to offspring.
- •Control centre of the cell
- •Contains chromosomes (DNA and genes)
- •Directs cell activities
- •Controls cell division and heredity
Why learn this
It directs all cell activities and passes on hereditary information.
💡 Memory trick
Nucleus = the 'brain' of the cell; chromosomes inside carry the genes.
BiologyThe Fundamental Unit of LifemediumWhy are mitochondria called the powerhouse of the cell?
Reveal answer ↓
What it is
Mitochondria release energy from food during respiration and store it as ATP.
Answer
Mitochondria are called the powerhouse of the cell because they release energy during cellular respiration by breaking down glucose in the presence of oxygen. This energy is stored in the form of molecules of ATP (adenosine triphosphate), which is the energy currency of the cell and is used to power all the cell's activities. Mitochondria have their own DNA and ribosomes.
- •Site of cellular respiration
- •Release energy from glucose
- •Store energy as ATP (energy currency)
- •Have their own DNA and ribosomes
Why learn this
They power every energy-needing process in the cell.
💡 Memory trick
Mitochondria = powerhouse; ATP = the energy currency they produce.
BiologyThe Fundamental Unit of LifemediumWhat are the functions of the rough and smooth endoplasmic reticulum?
Reveal answer ↓
What it is
The endoplasmic reticulum is a network of membranes for transport; ribosomes on the rough ER make proteins.
Answer
The endoplasmic reticulum (ER) is a network of membrane-bound tubes and sheets inside the cell. The rough endoplasmic reticulum (RER) has ribosomes attached to its surface and helps in the synthesis and transport of proteins. The smooth endoplasmic reticulum (SER) has no ribosomes and helps in the synthesis of fats (lipids) and in detoxifying poisons. Ribosomes are the sites where proteins are actually made.
- •ER: network for transport within the cell
- •RER (with ribosomes): protein synthesis
- •SER: fat synthesis and detoxification
- •Ribosomes are the sites of protein synthesis
Why learn this
Together they build and move the proteins and fats a cell needs.
💡 Memory trick
Rough ER (with ribosomes) = protein factory; Smooth ER = fat/lipid maker.
BiologyThe Fundamental Unit of LifemediumState the functions of the Golgi apparatus and lysosomes.
Reveal answer ↓
What it is
The Golgi apparatus packages and dispatches materials; lysosomes are the cell's digestive and cleaning bags.
Answer
The Golgi apparatus is a stack of membrane-bound sacs that receives materials from the endoplasmic reticulum, then modifies, packages and dispatches them to various targets inside or outside the cell; it also helps form lysosomes. Lysosomes are membrane-bound sacs filled with digestive enzymes that break down worn-out cell parts and foreign material; because they can burst and digest their own cell when it is damaged, they are called the suicidal bags of the cell.
- •Golgi: modifies, packages and dispatches materials
- •Golgi helps form lysosomes
- •Lysosomes: contain digestive enzymes
- •Lysosomes = suicidal bags (self-cleaning)
Why learn this
They keep the cell organised and clean up worn-out parts.
💡 Memory trick
Golgi = post office (packing and dispatch). Lysosome = 'suicidal bag' (self-cleaning).
BiologyThe Fundamental Unit of LifeeasyWhat are plastids? State the function of the vacuole.
Reveal answer ↓
What it is
Plastids (like chloroplasts) are found in plant cells and help in food-making and colour; vacuoles store water and other substances.
Answer
Plastids are organelles found only in plant cells. The green plastids called chloroplasts contain chlorophyll and carry out photosynthesis, while coloured plastids (chromoplasts) give colour to flowers and fruits and colourless plastids (leucoplasts) store food. The vacuole is a fluid-filled sac that stores water, food, wastes and other substances; in plant cells the large central vacuole also provides turgidity and rigidity to the cell.
- •Chloroplasts: photosynthesis (contain chlorophyll)
- •Chromoplasts: colour; leucoplasts: storage
- •Vacuole stores water, food and wastes
- •Large vacuole keeps plant cells firm (turgid)
Why learn this
Chloroplasts let plants photosynthesise, and large vacuoles keep plant cells firm.
💡 Memory trick
Chloroplast = green food factory; Vacuole = storage tank (big in plant cells).
Browse by grade & subject
Concept-first question banks with model answers, the why, and a memory trick — one page per subject.