Honors Biology Cell Exam

Who coined the term 'cells' after observing cork in 1665?

Robert Hooke coined the term 'cells'.

What significant discovery did Anton Van Leeuwenhoek make in 1674?

He was the first person to observe and describe living cells.

What did Matthias Schleiden conclude in 1838 about plants?

All plants are entirely composed of cells.

What did Theodor Schwann conclude in 1839 about animals?

All animals are entirely composed of cells.

What was Rudolph Virchow's contribution to cell theory in 1855?

He proposed that all cells come from pre-existing cells.

What is the first pillar of cell theory?

All living things are composed of one or more cells.

What is the second pillar of cell theory?

Cells are the basic units of structure and function in an organism.

What is the third pillar of cell theory?

Cells come only from the reproduction of existing cells.

What limits the size of most cells?

The ratio between their outer surface area and their internal volume.

How do nerve cells reflect their function?

Nerve cells possess long extensions to send and transmit signals.

How do skin cells reflect their function?

Skin cells have a flat shape suited for covering and protecting the body surface.

How do white blood cells reflect their function?

White blood cells can change shape, allowing them to navigate through narrow tissue openings.

What are prokaryotes?

Cells that lack a true nucleus and organelles.

What are eukaryotes?

Cells that have a true nucleus and membrane-bound organelles.

What is the structure of the cell membrane?

Described by the Fluid Mosaic Model, consisting of a lipid bilayer and embedded proteins.

What is the function of the cell membrane?

It regulates internal conditions by controlling what enters and exits the cell.

What does the cytoplasm do?

It suspends organelles and is the active site for producing enzymes and proteins.

What is the role of the nucleus in eukaryotic cells?

It regulates and controls most functions of the cell.

What surrounds the nucleus?

The nuclear envelope, a double membrane.

What is the function of the nucleolus?

It is involved in the synthesis of ribosomes.

What do ribosomes do?

They assemble polypeptides by translating the genetic code from mRNA.

What is the role of rough ER?

Involved in membrane and antibody production, covered with ribosomes.

What does smooth ER synthesize?

It synthesizes lipids and detoxifies drugs and poisons.

What does the Golgi apparatus do?

It packages, sorts, and ships cell materials.

What is the function of mitochondria?

Sites of cellular respiration and ATP production.

What is simple diffusion?

The passive movement of molecules down a concentration gradient until evenly spread.

What types of molecules can easily diffuse through the lipid bilayer?

Small, hydrophobic (non-polar) molecules.

What factors regulate the rate of diffusion?

Steepness of gradient, temperature, surface area, and type of molecule.

What is osmosis?

The specific diffusion of water molecules across a membrane.

What does facilitated diffusion require?

Assistance from a specific transport channel protein, known as a carrier protein.

What is the purpose of the Sodium-Potassium pump?

To maintain vital chemical gradients across cell membranes.

What are protein pumps used for?

To pump molecules or ions against their concentration gradient, requiring energy.

How does bulk transport occur?

Materials are packaged into vesicles for transport into or out of the cell.

What is the active input of cellular energy needed for?

To move molecules against their concentration gradient in active transport.

How does lactose intolerance relate to osmosis?

Lactose causes water to leave intestinal cells, leading to clinical symptoms.

What happens to animal cells in a hypertonic solution?

They lose water and shrivel (crenate).

What happens to plant cells in a hypotonic solution?

They gain water, become turgid, and maintain structure.

How do animal cells react to isotonic solutions?

They maintain their shape and volume.

What is the result of a plant cell in a hypertonic solution?

The cell membrane pulls away from the cell wall (plasmolysis).

What is tonicity?

The effect of solute concentration on the movement of water across cell membranes.

What is a key characteristic of the Golgi apparatus?

It has distinct cis and trans sides for packaging materials.

Which organelle is known as the control center of the cell?

The nucleus.

What is the primary energy currency produced in mitochondria?

ATP (adenosine triphosphate).

What is the importance of the fluid mosaic model?

It describes the dynamic nature of the cell membrane.

Why do larger molecules require facilitated diffusion?

They are too large or charged to pass directly through the lipid bilayer.

What is the function of desmosomes?

They provide adhesion between cells in tissues.

Why is the nucleus referred to as the cellular headquarters?

It contains the cell's genetic material and controls cellular functions.

How does temperature affect the rate of diffusion?

Higher temperatures lead to faster molecular movement and quicker diffusion.