Biology Chapter: Cell Theory and Types

Lipids and Energy Storage

• Fatty acids are the primary component responsible for the energy storage function of lipids.
• Glycolipids, a type of lipid, contain a polar head with an oligosaccharide.

Nucleic Acids: Information Carriers

• Nucleic acids primarily function in storing and transmitting genetic information.
• DNA (deoxyribonucleic acid) is a type of nucleic acid composed of deoxyribonucleotides.

Fatty Acids: Building Blocks of Lipids

• Fatty acids can be saturated (no double bonds) or unsaturated (contain double bonds).

Cell Membrane: The Gatekeeper

• The cell membrane is responsible for regulating the passage of molecules into and out of the cell.

Cellular Organization

• Unicellular organisms consist of a single cell.
• Multicellular organisms are composed of multiple cells, each specialized for a specific function.

The Fundamental Principle of Cell Theory

• A key characteristic of the Cell Theory is that all living organisms are composed of one or more cells.

Prokaryotes vs. Eukaryotes: Cellular Differences

• Prokaryotic cells lack a nucleus and other membrane-bound organelles, whereas eukaryotic cells possess both.

DNA: The Blueprint of Life

• DNA is the macromolecule responsible for storing genetic information.

The Birth of New Cells

• Cell division is the process by which all cells arise from pre-existing cells.

The Basic Unit of Life

• The cell is the smallest unit of life that can survive independently.

Nucleus: DNA's Safe Haven

• The nucleus in eukaryotic cells serves to isolate DNA from the cytoplasm.

Distinguishing Features of Eukaryotic Cells

• Eukaryotic cells are distinguished from prokaryotic cells by the presence of a nucleus and other membrane-bound organelles.

Cell Membrane: A Dynamic Barrier

• The primary function of the cell membrane is to regulate the passage of molecules into and out of the cell.

Mitochondria: Cellular Powerhouses

• Mitochondria are responsible for generating energy (ATP) through cellular respiration.

The Fluid Mosaic Model

• The cell membrane is commonly referred to as the fluid mosaic model because of its dynamic and diverse composition.

Cytoskeleton: The Cell's Internal Scaffolding

• The cytoskeleton provides structural support, facilitates cell movement, and aids in organelle transport.

The Origins of Eukaryotic Cells

• Endosymbiotic theory suggests that eukaryotic cells evolved from prokaryotic cells through a process of engulfing and incorporating other prokaryotic cells.

Ribosomes: Protein Factories

• Ribosomes are primarily associated with protein synthesis.

Endoplasmic Reticulum: A Cellular Expressway

• The endoplasmic reticulum (ER) plays a key role in protein synthesis, folding, and transport.

Rough vs. Smooth ER: Distinctive Features

• Rough ER is characterized by the presence of ribosomes attached to its surface, whereas smooth ER lacks ribosomes.

Ribosomal Differences in Prokaryotes and Eukaryotes

• Prokaryotic ribosomes are smaller in size (70S) than eukaryotic ribosomes (80S).

Lysosomes: The Cell's Recycling Centers

• Lysosomes are referred to as "suicide bags" because they contain hydrolytic enzymes that can break down cellular debris and waste products.

Centrosomes: Organizing Cell Division

• Centrosomes play a crucial role in organizing microtubules, particularly during cell division.

Ribosomes: The Protein Builders

• Ribosomes are essential for protein synthesis, translating genetic information from mRNA into proteins.

Centrosomes: Guiding Cell Division

• Centrosomes are found primarily in animal cells and are involved in organizing microtubules, which are important for separation of chromosomes during cell division.

The Primary Structure of Proteins

• The primary structure of a protein refers to the linear sequence of amino acids.

Nucleosides: Building Blocks of Nucleic Acids

• Nucleosides consist of a nitrogenous base and a sugar molecule.

Polypeptides vs. Proteins: Structural Hierarchy

• Polypeptides are chains of amino acids, while proteins are polypeptides that have folded into specific three-dimensional structures.

Polysaccharides: Complex Carbohydrates

• Polysaccharides are complex carbohydrates composed of multiple monosaccharide units linked together.

Monosaccharides: Simple Sugars

• Monosaccharides are the simplest form of carbohydrates and are characterized by a single sugar unit.

Peptide Bonds: Linking Amino Acids

• Peptide bonds are the covalent bonds that link amino acids together in a polypeptide chain.

Disaccharides: Sugar Pairs

• Disaccharides are formed by the combination of two monosaccharides. Examples include sucrose, lactose, and maltose.

Oligosaccharides: Short Sugar Chains

• Oligosaccharides are short chains of monosaccharides, typically containing 2 to 10 units. They play roles in cell recognition and signaling.