BABS1201 Cellular Biology Overview

Summary of BABS1201 Lectures

• This document contains lecture notes covering topics related to molecules, cells, and genes from the University of New South Wales.
• The notes cover major elements of life, water's properties, cell structure/classification, energy transfer, and the details of photosynthesis and respiration.
• The notes explain core concepts of cellular biology and biochemistry at a basic level.

Major Elements of Life

• Major elements essential for life include carbon (CHOs, food sources), nitrogen (nucleic acids, amino acids), sulfur (amino acids), hydrogen, and oxygen.
• Phosphorus is also a key element in DNA and ATP.

Water Properties

• Water's shape and function are influenced by water's role as a solvent and it's properties (e.g. cohesion, adhesion).
• Water's polarity leads to interactions essential for life processes (e.g. biochemical reactions).
• Water's high specific heat capacity makes it important as a temperature regulator in biological systems, supporting various life processes.

Components of Life

• Organic molecules can be synthesized abiotically.
• Stanley Miller's experiment mimicked early Earth conditions.
• Water and electrical activity enable formation of biological particles.

Classification of Life - Cells

• Three domains - Bacteria, Archaea, and Eukarya.
• Cells have a common structure (e.g. plasma membrane, ribosomes, cytoplasm) and function to maintain life.
• Viruses aren't considered living as they can't metabolize or reproduce independently, dependent on a host.
• Prions are not living and cause a protein disease.

Endosymbiosis

• Mitochondria and chloroplasts evolved from prokaryotic cells, via endosymbiosis.
• These organelles use their own DNA, RNA, and ribosomes for protein synthesis.

Cell Structure and Function

• Eukaryotic cells have membrane-bound organelles (e.g. nucleus, endoplasmic reticulum, Golgi apparatus, etc).
• Prokaryotic cells lack membrane-bound organelles.
• Specialized cell structures and membranes are crucial for cell function, such as cytoskeleton components, and membrane proteins.

Enzymes

• Enzymes catalyze reactions by lowering activation energy.
• Factors such as substrate concentration, temperature, and pH influence enzyme activity.
• Enzyme inhibition can either be competitive or non-competitive, affecting how the enzyme works.

Metabolic Concepts

• Metabolism encompasses all chemical reactions in a cell, with catabolism breaking down molecules for energy and anabolism building up molecules from smaller pieces.
• Respiration, including glycolysis, citric acid cycle and oxidative phosphorylation, extract energy from food molecules.
• Photosynthesis, a critical part of the carbon cycle, uses light energy to produce sugars from carbon dioxide and water.

Metabolic Pathways

• Glycolysis, the TCA cycle, and oxidative phosphorylation are crucial stages in cellular respiration.
• These processes produce energy (ATP) through chemical oxidation and reduction reactions.
• ATP, a critical energy currency in cells, is generated from the breakdown of molecules.

Photosynthesis

• Light reactions in photosynthesis convert light energy to chemical energy (ATP and NADPH), while the Calvin cycle uses these products to fix carbon dioxide and synthesize glucose.
• The process of photosynthesis supports the oxygen and carbon cycles, and is essential for plant growth.

Membrane Proteins

• Membrane proteins are integral to maintaining cell integrity.
• Different membrane mechanisms, such as diffusion, facilitated diffusion, active transport, and osmosis may be involved depending on concentration gradients.
• Proteins may selectively transport molecules into or out of cells.
• Membrane potential is generated by the difference in the distribution of ions across cell membranes.

Cellular Respiration:

• Aerobic respiration requires oxygen, generating many ATP molecules, while fermentation (anaerobic respiration) doesn't utilize oxygen, producing less energy.

DNA Replication

• DNA replication follows a semi-conservative model, with each new DNA molecule containing one original strand and one newly synthesized strand.