Study Guide for Test 2 (Chapters 4 & 5): Biochemistry and Tissue Types

Anabolism vs. Catabolism

Definitions and Examples

Metabolism consists of two complementary processes: anabolism and catabolism. These processes are essential for maintaining cellular function and energy balance.

• Anabolism: The synthesis of complex molecules from simpler ones, requiring energy input. Example: Protein synthesis from amino acids.

• Catabolism: The breakdown of complex molecules into simpler ones, releasing energy. Example: Breakdown of glucose during cellular respiration.

Enzymes

Nomenclature, Role, and Function

Enzymes are biological catalysts that speed up chemical reactions without being consumed. They are typically named based on the substrate they act on or the reaction they catalyze (e.g., lipase breaks down lipids).

• Role: Lower activation energy of reactions.

• Function: Facilitate metabolic pathways, regulate reaction rates.

Hydrolysis vs. Dehydration Synthesis

Water Molecule Involvement

These are two fundamental types of chemical reactions in biochemistry:

• Hydrolysis: Breaking down molecules by adding water. Example: Digestion of starch into glucose.

• Dehydration Synthesis: Forming larger molecules by removing water. Example: Formation of peptide bonds between amino acids.

ATP

Role in Cellular Processes

Adenosine triphosphate (ATP) is the primary energy carrier in cells. It provides energy for various cellular activities, including muscle contraction, active transport, and biosynthesis.

• Equation:

$\text{ATP} \rightarrow \text{ADP} + \text{P}_i + \text{energy}$

Coenzymes

Role and Examples

Coenzymes are organic molecules that assist enzymes in catalyzing reactions. They often act as carriers for chemical groups or electrons.

• Examples: NAD+, FAD, Coenzyme A

Cellular Respiration

Steps, Locations, and Products

Cellular respiration is the process by which cells extract energy from glucose. It occurs in several stages:

• Glycolysis: Cytoplasm; produces pyruvate, ATP, NADH

• Krebs Cycle: Mitochondrial matrix; produces CO2, ATP, NADH, FADH2

• Electron Transport Chain: Inner mitochondrial membrane; produces ATP and water

NAD+ and FADH2

Roles in Energy Transfer

These coenzymes are crucial for transferring electrons during cellular respiration, facilitating ATP production.

• NAD+: Accepts electrons to become NADH

• FAD: Accepts electrons to become FADH2

Aerobic vs. Anaerobic Respiration

Differences and Outcomes

Aerobic respiration requires oxygen and produces more ATP, while anaerobic respiration occurs without oxygen and yields less ATP.

• Aerobic: Glucose + O2 → CO2 + H2O + ATP

• Anaerobic: Glucose → Lactic acid (in animals) or ethanol (in yeast) + ATP

Genetic Information

Definitions

Genetic information refers to the instructions encoded in DNA that determine the traits and functions of living organisms.

DNA & RNA

Structure, Replication, Transcription, Translation, Codons

• DNA: Double helix, stores genetic information

• RNA: Single-stranded, involved in protein synthesis

• Replication: Copying DNA before cell division

• Transcription: DNA → mRNA

• Translation: mRNA → Protein

• Codons: Triplets of nucleotides in mRNA that specify amino acids

Types of RNA and Their Roles

• mRNA (messenger RNA): Carries genetic code from DNA to ribosomes

• tRNA (transfer RNA): Brings amino acids to ribosomes during translation

• rRNA (ribosomal RNA): Forms part of the ribosome structure

Tissue Types

Four Basic Types and Their Functions

There are four primary tissue types in animals:

• Epithelial Tissue: Covers surfaces, lines cavities, forms glands

• Connective Tissue: Supports, binds, and protects organs

• Muscle Tissue: Enables movement

• Nervous Tissue: Transmits electrical signals

Epithelial Tissue

Characteristics, Locations, Layering

• Characteristics: Tightly packed cells, little extracellular matrix

• Locations: Skin, lining of digestive tract, glands

• Layering: Simple (one layer), stratified (multiple layers)

Connective Tissue

Types, Components, Binding Properties

• Types: Loose, dense, cartilage, bone, blood

• Components: Cells, fibers (collagen, elastin), ground substance

• Binding Properties: Provides support, connects tissues, stores energy

Muscle Tissue

Types, Type of Control, and Locations

• Skeletal Muscle: Voluntary control, attached to bones

• Cardiac Muscle: Involuntary control, found in heart

• Smooth Muscle: Involuntary control, found in walls of organs

Nervous Tissue

Basic Function and Structure

• Function: Conducts electrical impulses, processes information

• Structure: Neurons (nerve cells) and neuroglia (supporting cells)

Membranes

Mucous, Serous, Synovial, Cutaneous – Locations and Functions

Membrane Type	Location	Function
Mucous	Lines cavities open to exterior (e.g., respiratory, digestive tracts)	Secretes mucus, protects and lubricates surfaces
Serous	Lines closed cavities (e.g., thoracic, abdominal)	Secretes serous fluid, reduces friction
Synovial	Lines joint cavities	Secretes synovial fluid, lubricates joints
Cutaneous	Skin	Protects body, prevents water loss