Topic 4- Cells & membrane

Flashcards covering cell theory, types of cells, functions of organelles, and membrane transport mechanisms.

Cell theory

All living things are made of one or more cells; cells are the basic structural unit of life; cells arise from pre-existing cells.

Organelles

Cellular structures that perform specific functions within a cell.

Prokaryotic cells

Unicellular organisms (e.g., Bacteria and Archaea) that lack a nucleus and membrane-bound organelles.

Eukaryotic cells

Cells of unicellular or multicellular organisms (e.g., Animals, plants, fungi, protists) that possess a nucleus and membrane-bound organelles.

Plasma membrane

A flexible barrier that controls what enters and leaves a cell, found in both prokaryotic and eukaryotic cells.

Cytoplasm

The jelly-like substance filling the cell, outside the nucleus, where organelles are suspended.

DNA

The genetic material found in cells, containing instructions for development and function.

Ribosomes

Cellular structures responsible for making proteins, found in both prokaryotic and eukaryotic cells.

Membrane-bound organelles

Structures within eukaryotic cells that are enclosed with a phospholipid bilayer, like the plasma membrane.

Nucleus

An organelle in eukaryotic cells that contains, controls, reads, and copies DNA.

Rough Endoplasmic reticulum

An organelle involved in the making and transport of proteins, studded with ribosomes.

Smooth Endoplasmic reticulum

An organelle involved in the synthesis of lipids.

Golgi apparatus

An organelle that receives, modifies, packages, and sends out proteins.

Vesicles

Small membrane-bound sacs that transport materials around the cell.

Lysosomes

Organelles containing digestive enzymes that break down organelles, bacteria, and molecules.

Mitochondria

Organelles responsible for cellular respiration, producing ATP (energy) for the cell.

Chloroplast

Organelles in plant cells that use sunlight to make sugars through photosynthesis.

Cell wall

A rigid outer layer in plant cells that provides shape and structural support.

Large central vacuole

A prominent organelle in plant cells that stores fluids and food, maintaining cell pressure.

Fluid mosaic model

A description of the plasma membrane as a flexible barrier embedded with proteins and other molecules.

Phospholipid bilayer

The structural basis of the plasma membrane, consisting of two layers of phospholipids with hydrophobic tails facing each other.

Selectively permeable

A property of plasma membranes meaning some substances can pass through, but not all.

Passive transport

Movement of molecules from a region of high concentration to a region of low concentration without requiring cellular energy.

Active transport

Movement of molecules from a region of low concentration to a region of high concentration, requiring cellular energy (ATP).

Diffusion

The natural movement of particles from an area of high concentration to an area of low concentration.

Osmosis

The diffusion of water across a selectively permeable membrane, moving relative to solute concentration.

Tonicity

The difference in concentration of solutes on either side of a membrane.

Isotonic

A condition where there is an equal concentration of solutes on both sides of a membrane.

Hypertonic

A condition where one side of a membrane has a higher concentration of solutes.

Hypotonic

A condition where one side of a membrane has a lower concentration of solutes.

Simple diffusion

Passive transport where small, uncharged, or nonpolar molecules diffuse directly across the phospholipid bilayer of a membrane.

Facilitated diffusion

Passive transport where molecules move across a membrane through a transport protein, driven by diffusion, for substances too large or charged.

ATP (adenosine triphosphate)

The primary energy currency used by cells to power active transport and other cellular processes.

Bulk transport

Active transport involving the movement of a mass of molecules across a membrane through the formation and fusion of vesicles.