Cell Structure and Function

These flashcards cover key concepts related to cell structure and function, focusing on organelles, their roles, and cellular processes.

What additional structure do some eukaryotic cells have besides the plasma membrane?

A protective cell wall.

What is a main constituent of a primary cell wall?

Cellulose.

What substance is found in the secondary cell wall that makes it stronger?

Lignin.

What does the term organelle refer to in cell biology?

Any well-defined subcellular structure that performs a particular function.

What is the central role of the nucleus in a eukaryotic cell?

It stores genetic material (DNA) and controls the characteristics of the cell.

What structures are formed from chromatin during cell division?

Chromosomes.

What is the function of ribosomes in a cell?

They are responsible for synthesizing proteins using messenger RNA as a template.

What comprises the endomembrane system in a eukaryotic cell?

Nuclear envelope, endoplasmic reticulum, Golgi apparatus, and vesicles.

What distinguishes the rough endoplasmic reticulum from the smooth endoplasmic reticulum?

The rough ER is studded with ribosomes, while the smooth ER is not.

What is the primary function of the Golgi apparatus?

It collects, sorts, packages, and distributes materials such as proteins and lipids.

What is the function of lysosomes?

They contain enzymes for intracellular digestion.

What role do vacuoles typically play in plant cells?

They store substances and provide structural support.

What is the primary function of peroxisomes?

They contain enzymes to break down hydrogen peroxide and other metabolites.

How do chloroplasts contribute to a plant cell?

They allow the cell to perform photosynthesis, using solar energy to produce organic molecules.

What is the role of mitochondria in eukaryotic cells?

They produce ATP through cellular respiration.

What does the cytoskeleton do in eukaryotic cells?

It maintains cell shape and allows movement of the cell and its organelles.

What are the structural differences between actin filaments, intermediate filaments, and microtubules?

Actin filaments are thin and flexible, intermediate filaments are rope-like and provide structural support, while microtubules are small hollow cylinders.

What is the fluid-mosaic model of the plasma membrane?

It describes the structure of the plasma membrane as a bilayer of phospholipids with embedded proteins that can move laterally.

What is the role of channel proteins in the plasma membrane?

They facilitate the passage of specific molecules across the membrane.

What occurs during diffusion?

Molecules move from an area of higher concentration to an area of lower concentration.

What is osmosis?

The diffusion of water across a selectively permeable membrane.

What happens to a cell in a hypertonic solution?

The cell shrinks due to loss of water.

What kind of proteins aid in the movement of molecules against their concentration gradient?

Active transport proteins or pumps.

What is phagocytosis?

The process by which a cell engulfs large substances by wrapping around them with its membrane.

What defines receptor-mediated endocytosis?

It is a selective process where specific molecules bind to receptors before being engulfed by the cell.

What are the two types of active transport?

Primary active transport and secondary active transport.

What is the importance of the sodium-potassium pump?

It helps maintain the electrical gradient and concentration gradients of sodium and potassium ions across the plasma membrane.

Which organelle is known as the 'powerhouse' of the cell?

Mitochondria.