Exam Revision Unit 1 2025

Flashcards based on lecture notes for exam revision.

What's the first part of the cell theory?

All living things are made of one or more cells.

What's the second part of the cell theory?

The cell is the smallest and most basic unit of life.

What's the third part of the cell theory?

All cells come from other cells that already exist.

What are the two kinds of cells?

Prokaryotic and Eukaryotic cells.

What makes a prokaryotic cell different?

It doesn't have parts with their own coverings (membrane-bound organelles).

How are prokaryotic cells in size and structure?

They're pretty small (0.2-2 μm) and not too complicated.

What's the cellularity of prokaryotic cells?

Made of just one cell (unicellular).

Do prokaryotic cells have a stable cytoskeleton?

No.

Describe the nucleus of a prokaryotic cell.

It doesn't have a separate nucleus; its DNA floats around inside the cell.

What are two examples of prokaryotic cells?

Bacteria and Archaea.

What makes a eukaryotic cell different?

It has parts with their own coverings (membrane-bound organelles).

How are eukaryotic cells in size and structure?

They're bigger (10-100 μm) and more complex.

What is the cellularity of eukaryotic cells?

Can be made of one cell (unicellular) or many cells (multicellular).

Where is DNA located in a Eukaryotic cell?

It's kept inside a nucleus.

Do eukaryotic cells have a stable cytoskeleton?

Yes, they usually have a cytoskeleton to keep their shape.

What are four examples of Eukaryotic cells?

Animals, Plants, Protists & Fungi.

What is the Cytoplasm?

The stuff inside the cell that takes up most of the space.

What is the Cytosol?

The fluid part, with enzymes, water, vitamins, and acids.

What makes up the Cytoplasm?

Cytosol + all the organelles.

What is the Plasma Membrane?

The cell's outer barrier that lets some things in and keeps others out.

What is the function of the Plasma Membrane?

It's the cell's doorway.

What is the Plasma Membrane composed of?

Made of lipids (fats) with protein channels.

What role does the Plasma Membrane play in the exchange of materials?

Stuff goes in and out of the cell through it.

What happens if the Plasma Membrane is damaged?

The cell will die.

What is the function of the Nucleus?

It controls what the cell does and how it divides.

What does the Nucleus contain?

The cell's DNA.

How is the Nucleus separated from the rest of the cell?

A membrane called the nuclear membrane.

What is the Nucleoli's role in the Nucleus?

They make ribosomes.

Do all human cells have Nuclei?

No, not all of them (like red blood cells).

What is the role of the Mitochondria?

The cell's power plant.

What process takes place in the Mitochondria?

Cellular respiration happens here.

What type of energy does the Mitochondria produce?

ATP.

In what kind of cell are Mitochondria found?

Eukaryotes.

What is the structure of the Mitochondria?

It has a folded inner membrane (cristae) and fluid inside (matrix).

What role do Cristae play?

They give lots of space for reactions.

What process takes place in the mitochondria?

Cellular Respiration.

What does cellular respiration do?

Breaks down glucose to make energy.

How does cellular respiration occur?

With or without oxygen.

What do Ribosomes look like?

Small black dots.

What takes place in the Ribosomes?

Proteins are made here (translation).

What are Ribosomes made of?

rRNA and protein.

What type of Cells have a large number of ribosomes?

Cells that make lots of protein.

Are Ribosomes found in prokaryotic cells?

Yes.

What is the function of the Endoplasmic Reticulum?

Tunnels inside the cell for moving stuff around.

Are the Endoplasmic Reticulum passive channels?

No, they work on the stuff they move.

What are the two types of Endoplasmic Reticulum?

Rough and Smooth ER.

What are the characteristics and function of Rough ER?

Covered in ribosomes to quickly change and send proteins.

What are the characteristics and function of Smooth ER?

No ribosomes. It does different jobs like moving stuff and cleaning out drugs (detoxification).

What is the Golgi Apparatus?

It's like a post office that sends stuff out of the cell.

How do materials arrive to the Golgi Body?

They come from the ER.

What is the function of the Golgi Body?

It changes the stuff, packages it, and sends it out in vesicles.

What do vesicles do?

They pop open and let their contents out of the cell.

Where can Chloroplasts be found?

Plants & algae.

What do Chloroplasts contain?

Green stuff (chlorophyll).

What is the function of Chloroplasts?

Photosynthesis.

What are the components of Chloroplasts?

Grana (stacks of membranes called thylakoids) and stroma (fluid).

Where does photosynthesis take place?

In the chloroplasts.

What is photosynthesis?

Using sunlight, carbon dioxide, and water to make glucose and oxygen.

What do thylakoid membranes contain?

Chlorophyll.

What is the first key difference between plant and animal cells?

Plant cells have a cell wall, but animal cells don't.

What is the second key difference between plant and animal cells?

Plant cells have chloroplasts, but animal cells don't.

What is the third key difference between plant and animal cells?

Animal cells have small vacuoles or none at all, while plant cells have one big one.

What are three ways of increasing the membrane surface area of cells without changing cell volume?

Cell Compartmentalisation, Flattened Shape and Plasma Membrane Extensions.

What does the Surface Area-to-Volume Ratio examine?

It looks at how much membrane a cell has compared to its cytoplasm.

What is the rate of metabolism a function of?

A function of a cell’s volume.

What is the rate at which material is exchanged a function of?

A function of a cell’s surface area.

What does the Surface Area-to-Volume Ratio of cells needs to be?

It needs to be high.

What are the Types of transport across the membranes?

Passive and Active transport

What are the subunits of the bilayer of the plasma membrane?

Phospholipids.

What is the state of the phosphate heads in the plasma membrane?

They like water and can dissolve in it.

What is the state of the fatty acid (lipid) tails in the plasma membrane?

They hate water and can't dissolve in it.

What are the three different processes of passive transport?

Diffusion, Osmosis and Facilitated diffusion.

What term do we use when describing differences in solute concentrations between two compartments?

We use the term tonicity.

What does Isotonic mean?

The fluids inside and outside the cell have the same amount of stuff dissolved in them.

What does Hypotonic mean?

Solutions with less stuff dissolved in them.

What does Hypertonic mean?

Solutions with more stuff dissolved in them.

What are the two types of bulk transport?

Exocytosis (stuff exiting) and endocytosis (stuff entering).

What kinds of transport are there in the transport summary?

Simple diffusion, Osmosis, Facilitated diffusion, Active transport, Exocytosis and Endocytosis.

What steps are involved in Prokaryotic Cell Division: Binary Fission?

DNA Replication, Chromosome Segregation and Cytokinesis.

What steps are involved in Eukaryotic Cell Division: The Cell Cycle?

Interphase, Mitosis and Cytokinesis.

What stages are involved in Interphase?

G1 Phase (Growth), S Phase (DNA Replication) and G2 Phase (Preparation).

What stages is the M Phase subdivided into?

Mitosis – The division of the nucleus and Cytokinesis – Division of the cytoplasm.

What occurs in the Prokaryotic Cell Cycle?

DNA Replication, Cytokinesis, Two Identical Daughter Cells.

What is Apoptosis?

Programmed cell death.

What is the function of Apoptosis?

To get rid of cells that aren't needed or are infected.

What does the G1 Checkpoint check?

Makes sure there are enough nutrients, the cell is the right size, and the DNA is okay before moving on.

What does the G2 Checkpoint check?

Makes sure the proteins for mitosis are ready, the cell is the right size, and the DNA has been copied correctly.

What does the Metaphase (Mitosis) Checkpoint check?

Checks that the chromosomes are attached to the mitotic spindle.

What are Stem Cells?

Cells that can turn into many different kinds of cells.

What types of Stem Cells exist?

Totipotent Stem Cell, Pluripotent Stem Cell and Multipotent Stem Cell.

How are Specialised cells organized?

They work together in tissues to do jobs that one cell can't do alone.

What is Xylem Tissue?

Tubes that carry water and minerals from the roots to the leaves.

What is Phloem tissue?

Tubes that carry sugars and nutrients around the plant.

What is common to both Vessel elements and Tracheids?

Hollow cells and Lignified cells

What are Phloem made up of?

Sieve cells and companion cells

What is Translocation?

Moving nutrients from the leaves to other parts of the plant.

What is Transpiration?

Water moving up and out of the plant through stomata.

What environmental conditions affecting the transpiration rate?

Temperature, Light, Humidity and Wind.

What is Physical Digestion?

Breaking down food into smaller pieces by chewing, muscle movement, etc.

What is Chemical Digestion?

Using enzymes and stomach acid to break food down.