Chapter 3: Cells - Vocabulary Flashcards

Vocabulary practice flashcards covering cell structures, membrane components, organelles, cellular adhesion molecules, and nuclear structures from Chapter 3.

Differentiated cells

Cells that have developed specialized structural and functional characteristics.

What is the basic unit of structure and function in the body?

The cell

An adult human body consists of

about 37 trillion cells

How are cell structure and function related?

They are inter-related; cells vary in size and shape based on their functions.

Composite cell

have three main parts

-cell membrane

•AKA plasma membrane

•Encircles the cytoplasm

-cytoplasm

•Contains organelles suspended in cytosol

•Organelles have specific functions

-nucleus

•Innermost, enclosed by a nuclear envelope, and contains genetic material

What does the cell membrane separate?

intracellular fluid from extracellular fluid

What are two characteristics of the cell membrane?

It is extremely thin and flexible.

What does selectively permeable mean?

The membrane controls what goes into and out of the cell.

Signal Transduction

The process by which the cell membrane allows the cell to receive and respond to incoming chemical messages.

What is the cell membrane primarily composed of?

Lipids and proteins

What is the main lipid structure of the cell membrane?

A phospholipid bilayer

Phospholipid Bilayer

A double-layered membrane structure consisting of water-soluble (hydrophilic) heads and water-insoluble (hydrophobic) fatty tails.

(Phospholipid bilayer)

What can pass through the fatty middle portion of the membrane?

Molecules that are soluble in lipids.

(Phospholipid bilayer)

What cannot pass through the fatty middle portion?

Water-soluble molecules.

What does cholesterol do?

Stabilizes the membrane and helps keep it impermeable to water-soluble substances.

Integral Proteins

Proteins that span the entire width of the phospholipid bilayer and may protrude on one or both sides.

Transmembrane Proteins

Integral proteins that protrude on both the intracellular and extracellular sides of the membrane bilayer.

Peripheral Proteins

Proteins associated with only one side of the membrane lipid bilayer.

Cell membrane protein functions:

Cellular Adhesion Molecules (CAMs)

Peripheral membrane proteins that enable cells to stick to each other and guide moving cells.

What is an example of CAM activity?

White blood cells traveling to a site of infection.

Selectin

A cellular adhesion molecule that allows immune cells to slow down and roll along blood-vessel walls.

Integrin

A cellular adhesion molecule that attaches cells to the extracellular matrix.

Cytoplasm

Cytosal + organelles

Cytosol

The liquid/fluid portion of the cytoplasm

Organelles

Tiny solid structures suspended in cytosol that perform specialized functions within a cell.

What are ribosomes made out of

Protein and RNA

Where are ribosomes found?

Scattered in the cytoplasm and attached to the ER.

Are ribosomes surrounded by a membrane?

No

What is the function of ribosomes?

Protein synthesis

Endoplasmic Reticulum (ER)

A widespread organelle made of membrane-bound flattened sacs and vesicles that transports molecules from nucleus out to the cell with parts that synthesize proteins and lipids.

Rough Endoplasmic Reticulum (RER)

ER with ribosomes attached to its outer surface that functions in protein synthesis, folding, and modification.

Smooth Endoplasmic Reticulum (SER)

ER lacking ribosomes that contains enzymes important for lipid synthesis.

What are vesicles?

Membranous sacs that vary in size and contents.

What do vesicles do?

Store or transport substances within or between cells.

How do vesicles form?

When part of the cell membrane folds inward and pinches off.

Golgi Apparatus

Organelle composed of flattened, membranous sacs that refines, packages, tags, sorts, and transports proteins formed in the rough ER.

What is the main function of Mitochondria?

Energy extraction

What are mitochondria known as?

The powerhouse of the cell

What do mitochondria produce?

ATP

Cristae

Folds of the inner mitochondrial membrane that increase surface area and harbor enzymes required for cellular respiration.

What else do mitochondria contain?

Some DNA (37 genes).

What are lysosomes sometimes called?

The “garbage disposals” of the cell.

What do lysosomes contain?

Powerful enzymes

What do lysosomes break down?

Proteins, carbohydrates, nucleic acids, foreign particles, and worn cellular parts.

Peroxisomes

Membranous cytoplasmic vesicles that resemble lysosomes.

What are peroxisomes especially abundant in?

Liver and kidney cells.

What do peroxisomes help with?

Breakdown of fatty acids and detoxification.

What does catalase do?

Decomposes hydrogen peroxide (H₂O₂).

Microfilaments

Cytoskeletal structures made of the protein actin that cause cellular movements and group together to form myofibrils in muscle cells.

Microtubules

Long, hollow tube structures made of the globular protein tubulin arranged in a spiral; critical for cell division.

Intermediate Fibers

Cytoskeletal elements composed of various proteins in different cells, abundant in skin cells and neurons.

Where is Centrosome located

In the cytoplasm near the nucleus.

What are centrioles made of?

Microtubules organized into 9 groups of 3.

What is the centrosome involved in?

Cell division and producing internal parts of cilia and flagella.

Cilia

Motile extensions

•Cilia (Latin for ‘eyelashes’)

•10 um long, attached to modified centriole

•Move in “to and fro” pattern

Flagella

Long, motile cellular extension that generates a swimming motion, such as on a sperm cell.

How many flagella does a cell usually have?

One

Nuclear Envelope

Double-layered lipid membrane enclosing the nucleus containing nuclear pores that allow mRNA out while retaining DNA.

What is the function of microvilli?

Increase surface area, leading to better absorption.

What are microvilli made of?

Actin

Are microvilli made of tubulin like cilia and flagella?

No

What does the Cell nucleus contain?

Genetic material.

What does the nucleus control?

Cell activities

What is the nuclear envelope and what does it contain?

A double-layered membrane surrounding the nucleus.

Nuclear pores that let out mRNA, but not DNA

Chromatin

Consists of cell’s 46 chromosomes

•Composed of DNA wound around proteins

•Tightness is dependent on which genes are being accessed