Biology A-Level Paper 1 Revision Guide

Introduction

• This lecture covers key topics for the AQA A-Level Biology Paper 1 exam.
• Use resources such as flashcards and notes for additional help.
• Topics include monomers, polymers, carbohydrates, lipids, proteins, DNA, RNA, and more.

Biological Molecules

Monomers and Polymers

• Monomers: Smaller units that can join to form polymers.
• Polymers: Large molecules formed from monomers; examples include starch, proteins, and nucleic acids.

Carbohydrates

• Monosaccharides: Single sugar units (e.g., glucose, fructose, galactose).
• Disaccharides: Two sugar units formed by glycosidic bonds (e.g., sucrose, maltose, lactose).
• Polysaccharides: Many sugar units; examples include starch, cellulose, glycogen.

Lipids

• Triglycerides: Composed of glycerol and three fatty acids; involved in energy storage.
• Phospholipids: Glycerol, two fatty acids, and a phosphate group; crucial for cell membranes.

Proteins

• Made from amino acids through peptide bonds.
• Have primary, secondary, tertiary, and quaternary structures.

Enzymes

• Catalysts that lower activation energy and speed up reactions.
• Specific to substrates due to their unique active sites.

DNA and RNA

DNA

• Contains genetic codes for protein synthesis.
• Double helix structure with base pairs (A-T, C-G).

RNA

• Types include mRNA, tRNA, and rRNA.
• Involved in protein synthesis and gene expression.

DNA Replication

• Semi-conservative process involving DNA polymerase.
• Ensures genetic information is passed to new cells.

Biological Processes

ATP

• Nucleotide derivative; stores and transfers energy within cells.
• Hydrolysis releases energy for cellular activities.

Water

• Essential solvent in biological systems.
• Involved in metabolism and temperature regulation.

Inorganic Ions

• Include sodium, potassium, calcium, etc.
• Play roles in nerve function, muscle contraction, and more.

Cell Structure and Function

Eukaryotic Cells

• Contain membrane-bound organelles (nucleus, mitochondria, etc.).
• Involved in processes like respiration and protein synthesis.

Prokaryotic Cells

• Lack membrane-bound organelles.
• Have circular DNA and smaller ribosomes.

Viruses

• Non-living particles that replicate inside host cells.
• Structure includes genetic material and protein coat.

Cell Division

Mitosis

• Division of eukaryotic cells into two identical daughter cells.
• Includes stages: prophase, metaphase, anaphase, telophase.

Meiosis

• Produces genetically diverse gametes.
• Involves two divisions leading to four haploid cells.

Membrane Transport

Types of Transport

• Simple Diffusion: Movement down a concentration gradient.
• Facilitated Diffusion: Involves protein channels/carriers.
• Active Transport: Requires energy to move substances against a gradient.
• Osmosis: Movement of water across membranes.

Immunity

Immune System

• Distinguishes between self and non-self cells.
• Includes phagocytes and lymphocytes.

Vaccination

• Provides immunity by exposing the immune system to antigens.
• Creates memory cells for future protection.

Monoclonal Antibodies

• Used in diagnostics and targeted therapies.

Topics in Gas Exchange and Transport

Gas Exchange

• Occurs in alveoli, gills, insect trachea, etc.
• Adaptations include large surface area and short diffusion paths.

Circulatory System

• Closed, double circulatory system in mammals.
• Blood vessels include arteries, veins, capillaries.

Plant Transport

Transpiration

• Loss of water vapor from plant leaves.
• Affected by light, temperature, humidity, wind.

Translocation

• Movement of sugars via the phloem.

Miscellaneous Topics

Genetic Diversity

• Importance for adaptation and survival.
• Influenced by mutations and sexual reproduction.

Classification

• Organisms are grouped into domains and kingdoms.
• Binomial nomenclature is used for naming species.

Biodiversity

• Measures include species richness and genetic diversity.
• Affected by human activities such as agriculture.