Fundamental Unit of Life (Part I)

Water is the primary solvent and the most abundant component in the cytoplasm of all living cells.

The plasma membrane is primarily composed of a lipid bilayer embedded with various proteins, often described by the fluid mosaic model.

Robert Brown discovered the nucleus in 1831 while studying orchid cells.

While the plasma membrane is made of lipids and proteins, it also contains carbohydrates (as glycoproteins or glycolipids), making the statement that it is made of lipids and proteins 'only' incorrect.

Diffusion is the movement of substances from a region of higher concentration to a region of lower concentration, which is the primary mechanism for gaseous exchange like oxygen and carbon dioxide in cells.

Endocytosis is the process by which cells ingest external materials by engulfing them in a portion of the cell membrane.

Schleiden, Schwann, and Virchow are the key figures associated with the formulation and modification of cell theory. Purkinje is known for coining the term protoplasm.

Hydra is a multicellular organism, whereas Amoeba, Paramecium, and Bacteria are classic examples of unicellular organisms.

The cell theory states that all living organisms are made of cells, the cell is the basic unit of life, and cells arise from pre-existing cells. The presence of organelles is a feature of eukaryotic cells, not a core tenet of cell theory.

Osmosis is specifically defined as the movement of water molecules across a semi-permeable membrane from a region of higher water concentration to a region of lower water concentration.

Robert Hooke coined the term 'cell' in 1665 after observing cork slices under a microscope.

Plant cells absorb water from the soil through their roots primarily via the process of osmosis.

Cellulose is a complex carbohydrate that provides structural strength to the cell walls of plants.

Chloroplasts are organelles found in the cytoplasm of plant cells, not within the nucleus.

In prokaryotic cells, the genetic material is not enclosed by a nuclear membrane and is referred to as the nucleoid.

Mitochondria are known as the powerhouse of the cell because they generate most of the cell's supply of adenosine triphosphate (ATP) through cellular respiration.

Ribosomes are the cellular structures responsible for protein synthesis by translating messenger RNA into polypeptide chains.

Lysosomes contain powerful digestive enzymes that can break down cellular components. They are called suicide bags because, if the cell is damaged, they can burst and digest the cell itself.

ATP (Adenosine Triphosphate) is the primary energy carrier in all living organisms. It stores and releases energy for various cellular processes.

Genes are specific sequences of nucleotides within DNA that code for functional products like proteins. They are the fundamental units of heredity.

Chloroplasts contain the pigment chlorophyll, which captures light energy for photosynthesis and gives plants their green color.

Mitochondria are known as the powerhouse of the cell because they produce ATP. Digestive enzymes are primarily found in lysosomes, not mitochondria.

The Golgi apparatus consists of stacks of flattened, membrane-bound sacs called cisternae. These structures are involved in modifying, sorting, and packaging proteins.

Rough endoplasmic reticulum (RER) is studded with ribosomes on its surface, which gives it a rough appearance and makes it active in protein synthesis. Smooth endoplasmic reticulum (SER) lacks ribosomes.

The presence of ribosomes on the surface of the endoplasmic reticulum is the defining feature that classifies it as 'rough' rather than 'smooth'.

The Golgi apparatus is involved in the modification, sorting, and packaging of proteins and lipids. Cell division is primarily managed by the nucleus and cytoskeleton, not the Golgi.

Plastids are organelles found in plant cells and algae, but they are not present in animal cells.

Leucoplasts are a type of plastid that lack pigments and are primarily used for the storage of starch, lipids, or proteins.

Cell walls are found in plants, fungi, and bacteria, but animal cells lack a cell wall.

Cytoplasmic streaming, or cyclosis, is the directed flow of cytosol and organelles around the cell, which facilitates the transport of materials.

The cell membrane (plasma membrane) is a universal feature of all living cells, acting as a selective barrier between the cell interior and the environment.

Chloroplasts and mitochondria are semi-autonomous organelles that contain their own circular DNA and ribosomes, supporting the endosymbiotic theory.

Peptidoglycan is a polymer consisting of sugars and amino acids that forms a mesh-like layer outside the plasma membrane of most bacteria, forming the cell wall.

Mitochondria are the powerhouse of the cell because they generate ATP. Lysosomes are the digestive/suicide bags.