David Biology

What is a cell?

The basic unit of life; cells perform life functions such as growth, metabolism, reproduction, response to stimuli, and maintaining internal balance.

Who first used the word “cell”?

Robert Hooke.

When did Robert Hooke first use the word “cell”?

1665.

What did Robert Hooke observe when he named cells?

Cork under a microscope, where he saw small box-like structures.

What are the three main principles of cell theory?

All living organisms are made of cells; the cell is the basic structural and functional unit of life; all cells come from pre-existing cells.

Who observed living microorganisms?

Antonie van Leeuwenhoek.

What did Matthias Schleiden contribute to cell theory?

He said plants are made of cells.

What did Theodor Schwann contribute to cell theory?

He said animals are made of cells.

What did Rudolf Virchow contribute to cell theory?

He said all cells come from pre-existing cells.

Who helped form the cell theory?

Schleiden and Schwann.

What is a prokaryotic cell?

A simple cell that does not have a true nucleus.

Where is DNA located in prokaryotic cells?

In the cytoplasm in a region called the nucleoid.

What are examples of prokaryotes?

Bacteria and archaea.

What major structures are absent in prokaryotic cells?

A nucleus and membrane-bound organelles.

What structures are present in prokaryotic cells?

DNA in nucleoid, ribosomes, cytoplasm, cell membrane, and often a cell wall.

What is a eukaryotic cell?

A cell with a true nucleus and membrane-bound organelles.

What are examples of eukaryotes?

Animals, plants, fungi, and protists.

Where is DNA located in eukaryotic cells?

Inside the nucleus.

What do both prokaryotic and eukaryotic cells have?

Ribosomes.

Which cell type is usually smaller, prokaryotic or eukaryotic?

Prokaryotic cells are usually smaller.

Which cell type is larger and more complex?

Eukaryotic cells.

What are animal cells?

Eukaryotic cells.

What do animal cells contain?

Nucleus, mitochondria, ribosomes, rough ER, smooth ER, Golgi apparatus, lysosomes, cell membrane, and cytoplasm.

What do animal cells not have?

Cell wall, chloroplasts, or a large central vacuole.

What are plant cells?

Eukaryotic cells.

What three structures distinguish plant cells from animal cells?

Cell wall, chloroplasts, and large central vacuole.

What is the plant cell wall made of?

Cellulose.

What is the function of chloroplasts in plant cells?

Photosynthesis.

What is the function of the large central vacuole in plant cells?

Water storage and support.

What are fungal cells?

Eukaryotic cells with a nucleus, mitochondria, ribosomes, cell membrane, and cell wall.

What is the fungal cell wall made of?

Chitin.

What are bacterial cells?

Prokaryotic cells.

What do bacterial cells have?

DNA in nucleoid, ribosomes, cytoplasm, cell membrane, and cell wall.

What do bacterial cells not have?

Nucleus, mitochondria, chloroplasts, Golgi apparatus, or endoplasmic reticulum.

What is an organelle?

A structure inside a cell that performs a specific function.

What is the function of the nucleus?

Contains DNA and controls cell activities.

Why does the nucleus control cell activities?

Because DNA contains instructions for making proteins.

What are the main roles of the nucleus?

Storing genetic information, controlling protein production, and controlling cell division.

What is the function of ribosomes?

They make proteins.

Where can ribosomes be found?

Free in the cytoplasm or attached to rough ER.

What is the function of rough ER?

Helps produce and transport proteins.

Why is rough ER called “rough”?

It has ribosomes attached to it.

What is the function of smooth ER?

Produces lipids, detoxifies harmful substances, and stores calcium in some cells.

Does smooth ER have ribosomes?

No.

What is the function of the Golgi apparatus?

Modifies, sorts, and packages proteins and lipids.

What is the simple protein pathway in the cell?

Ribosome → rough ER → Golgi apparatus → vesicle → destination.

What is the function of mitochondria?

Produce ATP energy.

What is ATP?

The main energy currency of the cell.

Why are mitochondria special?

They have a double membrane, their own DNA, and their own ribosomes.

What theory is supported by mitochondria having their own DNA and ribosomes?

Endosymbiotic theory.

What does endosymbiotic theory say about mitochondria?

Mitochondria may have evolved from ancient bacteria living inside larger cells.

Where are chloroplasts found?

In plants and algae.

What do chloroplasts perform?

Photosynthesis.

What pigment do chloroplasts contain?

Chlorophyll.

What is chlorophyll?

The green pigment that absorbs light energy.

Why are chloroplasts special?

They have a double membrane, their own DNA, and their own ribosomes.

What is the function of lysosomes?

Digest waste, old organelles, foreign particles, and large molecules.

What do lysosomes contain?

Digestive enzymes.

What is the function of vacuoles?

Storage.

What does the large central vacuole do in plant cells?

Stores water and helps maintain turgor pressure.

What is turgor pressure?

Pressure inside a plant cell that helps keep the plant firm.

What is the function of the cell membrane?

Controls what enters and leaves the cell.

What is the function of the cell wall?

Provides support and protection.

What is cytoplasm?

Jelly-like fluid where many reactions happen.

What does selectively permeable mean?

Allows some substances to pass through but blocks others.

What is the cell membrane mainly made of?

A phospholipid bilayer.

What are the two parts of a phospholipid?

A hydrophilic head and hydrophobic tails.

What does hydrophilic mean?

Water-loving.

What does hydrophobic mean?

Water-fearing.

How are phospholipids arranged in the cell membrane?

Hydrophilic heads face the watery outside and inside; hydrophobic tails face inward away from water.

Why is the membrane called fluid mosaic?

Fluid because phospholipids and proteins can move; mosaic because many different proteins are embedded in the membrane.

What is an integral protein?

A protein embedded inside the membrane.

What is a transmembrane protein?

A protein that crosses the entire membrane.

What is a peripheral protein?

A protein attached to the surface of the membrane.

What is a channel protein?

A protein that allows substances to pass through.

What is a carrier protein?

A protein that changes shape to move substances.

What is a receptor protein?

A protein that receives signals from outside the cell.

If a protein is inside the phospholipid bilayer, what is it?

An integral protein.

If a protein crosses the whole membrane, what is it?

A transmembrane protein.

What are the two main types of transport across the cell membrane?

Passive transport and active transport.

What is passive transport?

Transport that does not require ATP and moves substances down their concentration gradient.

What direction does passive transport move substances?

High concentration to low concentration.

What are the types of passive transport?

Diffusion, osmosis, and facilitated diffusion.

What is diffusion?

Movement of particles from high concentration to low concentration.

What molecules can move by diffusion?

Oxygen and carbon dioxide.

What is osmosis?

Diffusion of water across a selectively permeable membrane.

Does osmosis require ATP?

No.

Is osmosis active transport?

No, osmosis is passive transport.

What is facilitated diffusion?

Passive transport through membrane proteins.

What proteins are used in facilitated diffusion?

Channel proteins or carrier proteins.

Why does facilitated diffusion not require ATP?

Substances still move from high concentration to low concentration.

What is active transport?

Transport that requires ATP and moves substances against their concentration gradient.

What direction does active transport move substances?

Low concentration to high concentration.

What are examples of active transport?

Sodium-potassium pump, proton pump, endocytosis, and exocytosis.

What is endocytosis?

Bringing substances into the cell using vesicles.

What is exocytosis?

Removing substances from the cell using vesicles.

What is phagocytosis?

Cell eating; the cell surrounds a large particle and brings it inside.

What is an example of phagocytosis?

Some white blood cells engulf bacteria.

What are the four main biomolecule groups?

Carbohydrates, lipids, proteins, and nucleic acids.

What are carbohydrates made of?

Monosaccharides.