Human Body Systems

What does cytology mean?

The study of cells, including their structure, function, and chemistry.

What is the cell theory?

All living things are made of cells, cells are the basic units of life, and all cells come from pre-existing cells.

Who are the three scientists that came up with the cell theory?

Matthias Schleiden, Theodor Schwann, and Rudolf Virchow.

How are cells limited in size?

By the surface area-to-volume ratio, which affects nutrient and waste exchange efficiency.

What does pro- mean?

Before or primitive.

What does karyo- mean?

Refers to the nucleus.

What are ribosomes?

Organelles that synthesize proteins by translating messenger RNA.

What is the nucleoid?

A region in prokaryotic cells where DNA is located, not enclosed by a membrane.

What does eu- mean?

True or good.

What does eukaryotic mean?

Cells with a true nucleus and membrane-bound organelles.

How big are animal cells compared to prokaryotic cells?

Animal cells are 10–100 times larger than prokaryotic cells.

What is the cell membrane?

A selectively permeable barrier that surrounds the cell and controls substance movement.

What does semi-permeable mean?

Allows certain substances to pass through while blocking others.

Describe the phospholipid bilayer.

A double layer of phospholipids with hydrophilic heads outward and hydrophobic tails inward.

What does philia mean?

Love or attraction.

What does phobic mean?

Fear or aversion.

What are microvilli?

Small projections that increase surface area for absorption.

What is the cytoplasm made up of?

Cytosol (fluid) and organelles, excluding the nucleus.

What happens when too much waste product accumulates in the cell?

It disrupts cell function and may lead to cell damage or death.

What do all living things need to be surrounded by?

A cell membrane.

What is the purpose of the phospholipid bilayer?

To protect the cell and regulate substance movement.

What are embedded proteins?

Proteins within the membrane that assist in transport and communication.

What are ion channels?

Proteins that allow specific ions to pass through the membrane.

What are transporter (carrier) proteins?

Proteins that bind and move substances across the membrane.

What are enzymes?

Biological catalysts that speed up chemical reactions.

What are receptor sites?

Membrane regions where molecules bind to trigger cellular responses.

What are recognition sites?

Membrane areas that help identify the cell to others, aiding immune response.

What are side effects?

Unintended or secondary effects of a drug or treatment.

What are immunosuppressant drugs?

Medications that reduce immune system activity.

Name two immunosuppressant drugs.

Cyclosporine and Azathioprine.

What is thalidomide?

A sedative once used for morning sickness; now used for multiple myeloma and leprosy under strict controls.

What is the side effect of thalidomide?

Severe birth defects, especially limb malformations, when taken during pregnancy.