Cells as the Basic Units of Life

This set of vocabulary flashcards covers the fundamental concepts of cell biology, including cell types, organelles, plant versus animal cell differences, and the nature and function of stem cells as described in the lecture notes.

Unicellular organism

An organism that consists of only one cell, such as bacteria.

Multicellular organism

An organism that consists of more than one cell (millions or billions), such as trees and blue whales.

Specialised cells

Different types of cells within a multicellular organism that each perform a specific function.

Cell wall

A non-living rigid layer found only in plant cells that consists of cellulose and provides shape and structure.

Middle lamella

One of the three layers of the plant cell wall that is made of sticky pectin.

Cell membrane

A thin double membrane made of a phospholipid bi-layer with embedded proteins that controls the movement of substances in and out of the cell.

Cytoplasm

A jelly-like substance containing a large amount of water where organelles are suspended and chemical reactions take place.

Nucleus

The organelle that contains the cell's DNA, chromatin network, and nucleolus, controlling all cell activities and hereditary information.

Mitochondrion

The organelle responsible for cellular respiration and providing energy to the cell, characterized by inner folds called cristae.

Chloroplast

An organelle found only in plant cells that contains chlorophyll and is the site of photosynthesis.

Thylakoids

Structures within the chloroplast that form stacks called grana.

Vacuole

An organelle used for storage and support; plant cells typically have one large central vacuole containing cell sap.

Tonoplast

The membrane that surrounds the vacuole.

Ribosomes

Organelles responsible for protein synthesis, which can be attached to the endoplasmic reticulum or floating in the cytoplasm.

Stem cells

Unspecialized or undifferentiated cells that have the ability to divide and develop into different types of specialized cells.

Embryonic stem cells

Stem cells found in the embryo that are capable of dividing into almost any cell type.

Adult stem cells

Stem cells found in specific locations in adults, such as bone marrow, that can only differentiate into a limited number of related cell types.

Meristems

Regions in plants (usually near shoot and root tips) where stem cells occur and can produce all types of plant cells throughout the plant's life.

Regenerative medicine

A field of research using stem cells to generate healthy cells to replace those affected by disease.

Muscle cells

Specialized cells that contract and relax to facilitate movement.

Nerve cells

Specialized cells that transfer electrical impulses along the nervous system.

Red blood cells

Specialized cells responsible for transporting oxygen throughout the body.

Hierarchy of biological organization

The levels of organization in living things: Organelle (\rightarrow) Cell (\rightarrow) Tissue (\rightarrow) Organ (\rightarrow) Organ system (\rightarrow) Organism.