OCR Biology Module 2 Quiz

Study Notes

Introduction to OCR Biology Module 2

Module 2 explores the interconnected biological processes within organisms, from cellular to organismal levels.
It builds upon Module 1 and delves further into complex biological concepts.

Biological Molecules

Carbohydrates include monosaccharides (e.g., glucose, fructose), disaccharides (e.g., sucrose, lactose), and polysaccharides (e.g., starch, glycogen, cellulose).
Lipids are composed of fatty acids and glycerol, crucial for energy storage, insulation, and hormone production. Examples include triglycerides and phospholipids.
Proteins, complex amino acid polymers, are essential for structural support, enzymes, transport, hormones, and defense mechanisms. Protein function is determined by its specific structure (primary, secondary, tertiary, and quaternary).
Nucleic acids (DNA and RNA) are the genetic material, carrying instructions for protein synthesis. DNA stores genetic information; RNA plays roles in protein synthesis and other cellular processes.

Enzymes

Enzymes are biological catalysts that accelerate biochemical reactions by lowering activation energy without being consumed.
Enzymes have specific active sites that bind to specific substrates, forming enzyme-substrate complexes.
Enzyme activity is affected by temperature, pH, and substrate concentration.
Inhibitors, either competitive or non-competitive, affect enzyme reactions by binding to the active site.

Cell Respiration

Cell respiration releases energy from glucose in stages, producing ATP.
Glycolysis occurs in the cytoplasm, yielding a small amount of ATP.
The Krebs cycle (citric acid cycle), in the mitochondrial matrix, produces further ATP, reducing NAD+ and FAD to NADH and FADH2 respectively.
The electron transport chain (inner mitochondrial membrane) utilizes NADH and FADH2 high-energy electrons to generate a proton gradient, driving ATP synthesis via oxidative phosphorylation.

Photosynthesis

Photosynthesis converts light energy into chemical energy (glucose) in chloroplasts.
The process occurs within the thylakoid membranes.
Light-dependent reactions capture light energy to produce ATP and NADPH, involving chlorophyll and other pigments.
Light-independent reactions (Calvin cycle) use ATP and NADPH to fix carbon dioxide and synthesize glucose.

Nucleic Acids and Protein synthesis

DNA's genetic information is transcribed into mRNA.
mRNA carries the genetic code to ribosomes, where it's translated into a protein via codons on mRNA, anticodons on tRNA, and the functioning ribosome.
Mutations in DNA sequence can lead to altered proteins.

Homeostasis

Homeostasis maintains stable internal conditions, regulating factors like temperature, blood glucose, and water balance.
Negative feedback mechanisms counteract deviations from the set point to maintain homeostasis.
Positive feedback mechanisms amplify change, although less common.

Excretion and Osmoregulation

Excretion removes metabolic waste products.
Osmoregulation controls water and salt balance.
Kidneys are crucial for excretion and osmoregulation, involving filtration, reabsorption, and secretion.

Transport in Plants

Plants transport water, mineral ions, and sugars via specialized systems (xylem and phloem).
Xylem moves water and mineral ions from roots to leaves.
Phloem moves sugars from sources (leaves) to sinks (growing tissues, roots).

Transport in Humans

Humans transport substances throughout their body through the circulatory system (heart, blood vessels, blood).
Blood carries oxygen, nutrients, hormones, and waste products.
The circulatory system maintains homeostasis.

Nervous System

The nervous system allows communication between organism parts.
Nerve impulses travel along neurons via action potentials.
The nervous system rapidly responds to internal and external stimuli.

Endocrine System

The endocrine system regulates numerous processes through hormones released into the bloodstream.
Hormones act on target cells to induce specific responses, aiding in homeostasis.

Reproduction

Asexual reproduction produces genetically identical offspring from one parent.
Sexual reproduction involves two parents producing genetically diverse offspring through gamete formation, fertilization, and development.

Description

This quiz covers the key concepts of Module 2 in OCR Biology, focusing on processes within organisms and the roles of biological molecules. Understand carbohydrates, lipids, and proteins and their significance in cellular functions and overall organismal health.