Cell structures and functions

A reliable record says that the visible cell came from one plant with many cells; does seeing just this cell make the source organism one-celled?

A membrane and a wall have different roles

A cell membrane separates the cell's contents from its surroundings and controls the movement of substances across that boundary

A cell wall is a supporting layer outside the membrane; having a wall does not remove the need for a membrane

Plant and fungal cells have walls, as do many bacterial cells; animal cells do not have cell walls

A structure is a part of a cell; its function is what it does; an organelle is a specialised structure within a cell

Match a boundary to exchange

A reliable record identifies the cell membrane in a typical living cell

Which description gives a main function of the cell membrane?

Cell membrane: controls the movement of substances into and out of the cell; distinguish controlling exchange from supporting the outside of a cell

Controls the movement of substances into and out of the cell

Distinguish support from exchange

Separate instructions from protein building

The cytoplasm contains the fluid and many cell structures inside the membrane; in a plant or animal cell it is outside the nucleus; many chemical reactions happen there

A nucleus contains most of a typical plant or animal cell's DNA; DNA carries instructions involved in cell activities

Ribosomes build proteins using the cell's instructions; storing instructions and building the proteins are different roles

Not all DNA is in a nucleus: mitochondria and chloroplasts contain some DNA, and bacterial DNA is not enclosed in a nucleus

Identify the instruction-containing structure

A reliable record identifies the nucleus in a typical living cell

Which description gives a main function of the nucleus?

Nucleus: contains most of a typical plant or animal cell's DNA, which carries instructions for cell activities; DNA carries instructions; a nucleus does not directly make every protein

Contains most of a typical plant or animal cell's DNA, which carries instructions for cell activities

Identify protein building

Photosynthesis is not respiration

Mitochondria carry out major stages of aerobic respiration, using oxygen to make energy stored in nutrients available for cell activities; they do not create energy from nothing

Chloroplasts use light in photosynthesis to make sugars from carbon dioxide and water; plant cells with chloroplasts also contain mitochondria and carry out respiration

Not every plant cell has chloroplasts; many root cells lack them but still use nutrients and respire

A large central vacuole contains cell sap and helps maintain pressure that supports many plant cells; loss of water can reduce firmness without making the wall disappear

Identify the light-using role

Use typical cells without turning them into universal rules

A typical animal cell and a typical leaf cell share a membrane, cytoplasm, nucleus, mitochondria and ribosomes

The leaf cell also has a wall, chloroplasts and a large central vacuole; those differences do not mean that the shared structures have disappeared

A fungal cell has a wall, membrane, nucleus, mitochondria and ribosomes but no chloroplasts; a wall alone therefore does not prove that a cell is from a plant

A bacterial cell has a membrane, cytoplasm, DNA and ribosomes, but no membrane-bound nucleus or mitochondria; bacteria can perform life processes without those organelles

These are introductory comparisons, not a claim that every specialised cell in an organism has an identical set of structures

DNA without a nucleus

A reliable bacterial-cell record lists a membrane, cytoplasm, ribosomes and DNA

It states that the DNA is not enclosed in a nucleus

Which conclusion follows?

Bacteria do not have a membrane-bound nucleus; the supplied record still identifies DNA and protein-building ribosomes

A living cell can contain DNA and ribosomes without a nucleus

Use a root-cell record

Check a universal wall claim

Predict the direct effect first

Name what changed, recall its ordinary function and identify the direct effect before predicting later effects on the whole cell or organism

If the membrane no longer controls exchange normally, regulated movement between the cell and surroundings is directly affected

If fewer ribosomes work while instructions and other conditions stay the same, protein-building capacity is directly reduced

Without light, light-dependent photosynthesis cannot continue; aerobic respiration can still continue when oxygen and nutrients remain available

Compare processes in darkness

Connect pressure with support

Compare both specimens in Wide and Close; track the dashed viewing region and cell boundaries; these drawings deliberately omit internal structures at both views

No nucleus is drawn when you choose Close; what follows from that omission?

Separate omitted, unresolved and absent

Omitted means a drawing leaves a feature out; unresolved means a viewing method does not distinguish its detail; neither automatically means absent

Individual ribosomes are not resolved by an ordinary light microscope; a reliable separate record can establish their presence

A model that uses two organelle symbols for explanation does not measure the number or scale of organelles in a real cell

Use the model's purpose and any reliable source record to decide which conclusions are justified

Combine an image with a reliable record

Make and check your own explanation

On paper, explain why a living plant root cell can lack chloroplasts and still use nutrients; name the relevant process and structure; this written task is for discussion rather than automatic marking

Model explanation: many root cells do not photosynthesise because they lack chloroplasts, but their mitochondria support aerobic respiration using oxygen and nutrients

Compare a teacher-selected cell model with a reputable micrograph or prepared slide under supervision; state which structures are actually resolved and which are known only from another source

Do not infer real organelle counts or dimensions from this schematic; scientific drawing, measurement, slide preparation and equipment use need separate supervised work

Connect structure, function and evidence

Distinguish membrane exchange from wall support, DNA instructions from ribosome protein building, and photosynthesis from respiration

Remember cytoplasm as an active region and the large plant vacuole's storage and pressure role

Use supplied cell records rather than assuming every plant cell has chloroplasts or every living cell has a nucleus

Match a stated change to its direct functional effect and keep picture omissions separate from evidence of absence