4.Macromolecules & Micro-Organisms In Disease

Biomolecules Overview Table

Biomolecule	Description	Examples	Monomer (Building Block)
Carbohydrates	Biomolecules consisting of carbon, hydrogen, and oxygen atoms	Sugars, starch, cellulose	Monosaccharides (e.g. glucose)
Lipids	Diverse group of organic compounds	Fats, waxes, fat-soluble vitamins, monoglycerides, diglycerides, phospholipids	Fatty acids + glycerol
Proteins	Large biomolecules made of one or more long chains of amino acids	Enzymes, antibodies, hemoglobin	Amino acids
Nucleic Acids	Large biomolecules in all cells and viruses	DNA, RNA (contain sugar, phosphate, nitrogenous base)	Nucleotides

What is Monomers?

🔑 Monomer (Building Block) Note

✔ Monomer:

• A molecule that reacts with other monomers to form a polymer chain.

• Example: Amino acids are monomers that build proteins.

Biomolecule Structures

Carbohydrates

Biomolecule Consisting of Carbon, Hydrogen, and Oxygen Atoms.

-Sugars, Starch, Cellulose

Type	Meaning	Description	Example
Monosaccharide	Mono = One	Single sugar unit (monomer of carbohydrates)	Glucose, Fructose
Disaccharide	Di = Two	Two monosaccharides joined together	Sucrose (glucose + fructose), Lactose (glucose + galactose), Maltose (glucose + glucose)
Polysaccharide	Poly = Many	Many monosaccharides linked together (polymer)	Starch, Cellulose, Glycogen

🔹 Carbohydrate Rule

✔ Most carbohydrates end in “-ose.”

Examples from the image:

• Glucose

• Fructose

• Lactose

• Maltose

• Sucrose

Why are Carbohydrates are important to an organism’s structure and function?

Cell Wall: Plant (Cellulose)

• Q: What carbohydrate makes up the plant cell wall?

  • A: Cellulose

• Q: What is the structural role of cellulose in plants?

  • A: It provides rigidity and structural support to plant cells.

Cell Wall: Fungi (Chitin)

• Q: What carbohydrate is found in the cell walls of fungi?

  • A: Chitin

• Q: Is chitin found in plant cell walls?

  • A: No, chitin is found in fungi, not in plants.

Cellular Respiration

• Q: Which carbohydrate is used in cellular respiration to produce ATP?

  • A: Glucose

• Q: Where does the conversion of glucose to ATP occur?

  • A: In the mitochondria

ATP (Adenosine Triphosphate)

• Q: What is ATP?

  • A: Adenosine Triphosphate, the primary energy currency of the cell

• Q: What macromolecule is essential for ATP production?

  • A: Carbohydrates (specifically glucose)

Carbohydrates

Cell Wall Component

Plant Cell Wall

Made of Cellulose

Fungi Cell Wall

Made of Chitin

Carbohydrates

Cellular Respiration

Glucose

Used to make ATP

ATP

Energy Molecule

ATP (Adenosine Triphosphate)

Produced in mitochondria using glucose

Plants store energy as starch; animals store it as glycogen

Lipids

Diverse group of organic compounds

Fats, waxes, fat-soluble vitamins, monoglycerides, diglycerides, phospholipids

Fatty acids + glycerol

Category	Concept	Example / Structure	Details
Lipids	Types of Lipids	Triglycerides, Phospholipids, Steroids	All are hydrophobic (repel water)
Lipid Breakdown	Subunits	Glycerol + Fatty Acids	Not true monomers (no repeating units)
Lipid Properties	Hydrophobic Nature	Do not dissolve in water	Key in forming cell membranes
Fun Fact	Monomer Exception	Lipids ≠ true polymers	No repeating monomer subunits like carbs or proteins
Lipid Functions	Missing from Image	Energy storage, insulation, cushioning, hormone production	Common TEAS test point

Why are Lipids are important to an organism’s structure and function?

1. Cell Membranes

• Q: What role do lipids play in the cell membrane?

  • A: They form the phospholipid bilayer that surrounds the cell.

• Q: Why is the lipid bilayer important?

  • A: It regulates what enters and leaves the cell.

2. Energy Storage

• Q: How do lipids compare to carbohydrates in energy storage?

  • A: Lipids store more energy per gram and are used for long-term storage.

• Q: What type of lipid is primarily used for energy storage?

  • A: Triglycerides.

3. Insulation

• Q: What lipid structure insulates neurons?

  • A: The myelin sheath.

• Q: What is the function of the myelin sheath?

  • A: It helps conduct electrical impulses along nerves.

• Q: How do lipids help regulate body temperature?

  • A: Fat insulates the body by trapping heat.

4. Hormones

• Q: Which type of hormones are made from lipids?

  • A: Steroid hormones.

• Q: Give an example of a steroid hormone.

Function	Structure / Role	Explanation
Cell Membranes	Phospholipid bilayer	Forms the boundary of all cells, controls entry/exit of substances
Long-Term Energy Storage	Triglycerides	Store more energy per gram than carbs or proteins
Insulation (Myelin)	Myelin Sheath (nerve cells)	Lipid-rich sheath that insulates neurons and helps transmit impulses
Insulation (Fat)	Adipose tissue	Helps with temperature regulation and physical protection
Hormones	Steroid-based (e.g., estrogen, testosterone)	Lipid-derived hormones regulate reproduction, metabolism, etc.

Extra TEAS Exam Points Not in the Image (But Important!)

Concept	Why It’s Important for the TEAS
Cholesterol in membranes	Helps maintain fluidity and structure of cell membranes
Lipids in digestion	Bile salts emulsify fats; lipase enzymes break them down
Lipid-soluble molecules	Only small nonpolar substances like oxygen, CO₂, and steroids can diffuse across membranes
Unsaturated vs. Saturated fats	Unsaturated = double bonds, liquid; Saturated = single bonds, solid

Protein

Why are Proteins are important to an organism’s structure and function?

🔹 Amino Acids

• Q: What is the monomer of proteins?

  • A: Amino acid

• Q: How many amino acids are used to build all proteins?

  • A: 20

🔹 Cell Membrane Proteins

• Q: What do protein channels do in the cell membrane?

  • A: Transport substances across the membrane

• Q: What is the function of receptor proteins?

  • A: Receive chemical signals from outside the cell

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🔹 Enzymes, Antibodies, Hormones

• Q: What is the function of enzymes?

  • A: Speed up chemical reactions

• Q: What role do antibodies play?

  • A: Fight infection and recognize foreign invaders

• Q: Name a protein hormone.

  • A: Insulin

Proteins

Large biomolecules made of one or more long chains of amino acids

Enzymes, antibodies, hemoglobin

Amino acids

Category	Concept	Examples / Details
Monomer	Amino Acid	Building block of protein
Protein Structure Role	Structural Proteins	Muscle tissue, Hair follicle (keratin), Collagen
Cell Membranes	Protein Channels & Receptors	Allow transport, act in signal reception
Functional Proteins	Enzymes	Speed up chemical reactions (e.g., digestive enzymes)
	Antibodies	Immune defense against pathogens
	Hormones	Chemical messengers (e.g., Insulin) regulating physiological functions
	Gene

✅ Extra TEAS Concepts Missing from the Image (But Important!)

Concept	TEAS Relevance
Protein Structure Levels	Primary, secondary, tertiary, quaternary structures define shape and function
Denaturation	Proteins lose function if shape changes due to pH or temperature
Peptide Bond	The covalent bond between amino acids
Protein Synthesis	Occurs in ribosomes; involves transcription (nucleus) and translation (cytoplasm)
Examples of Enzymes	Amylase (breaks starch), pepsin (digests protein), DNA polymerase

Nucleic Acids

🔹 Nucleotide Structure

• Q: What are the three parts of a nucleotide?

  • A: Sugar, phosphate group, nitrogenous base

• Q: What sugar is found in DNA nucleotides?

  • A: Deoxyribose

• Q: What sugar is found in RNA nucleotides?

  • A: Ribose

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🔹 Nitrogenous Bases and Pairing

• Q: What base does adenine pair with in DNA?

  • A: Thymine

• Q: What base does adenine pair with in RNA?

  • A: Uracil

• Q: Which bases pair together?

  • A: Adenine–Thymine (DNA) or Adenine–Uracil (RNA), Cytosine–Guanine

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🔹 Function and Importance

• Q: What is the main function of DNA?

  • A: Store genetic information

• Q: What is the main role of RNA?

  • A: Help in protein synthesis

Category	Concept	Details / Examples
Monomer	Nucleotide	Made of sugar (deoxyribose or ribose), phosphate group, nitrogenous base
Nitrogenous Bases	Base Pairing	A pairs with T (DNA) / U (RNA), C pairs with G
Types of Nucleic Acids	DNA and RNA	DNA stores genetic info; RNA helps with protein synthesis
Function	Genetic Information Storage	Carry instructions for making proteins and cellular functions

Nucleotide is the Monomer of Nucleic Acids

✅ Extra TEAS Exam Points Not in the Image

Concept	Importance for TEAS
DNA Double Helix	DNA’s structure enables stable storage of genetic info
Types of RNA	mRNA, tRNA, rRNA each play roles in protein synthesis
Nucleotide Bond Types	Phosphodiester bonds link nucleotides; hydrogen bonds between bases
Central Dogma	DNA → RNA → Protein (transcription and translation)

Micro-Organisms in Biology - Viruses — Key Features

🧠 Flashcard Questions for Viruses (TEAS) 🔹 General Characteristics

• Q: Are viruses considered living cells?

  • A: No, viruses are not cells and are not considered alive.

• Q: What kind of parasite is a virus?

  • A: An intracellular obligate parasite—they need a host cell to reproduce.

• Q: What does a virus’s genome consist of?

  • A: Either RNA or DNA.

• Q: What is the outer protein coat of a virus called?

  • A: Capsid.

• Q: What is the typical size range of viruses?

  • A: 20 to 400 nanometers.

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🔹 Diseases Caused by Viruses

• Q: Name a viral disease that affects the respiratory tract.

  • A: Common cold, influenza, or COVID-19.

• Q: Which virus causes gastrointestinal illness?

  • A: Rotavirus.

• Q: What viral infection affects the skin?

  • A: Human papillomavirus (HPV).

• Q: Which virus affects the central nervous system?

  • A: Rabies virus.

Viruses — Key Features

Category	Details
Size	20–400 nanometers (nm)
Structure	Genome (RNA or DNA) inside a protein coat called Capsid; sometimes an Envelope
Characteristics	- Not a cell - Not alive - Intracellular obligate parasite (requires host cell to reproduce) - Has capsid (outer covering) - Contains genome (RNA or DNA) - May have an envelope
Disease Examples	- Respiratory: common cold, influenza, COVID-19 - GI tract: rotavirus - Systemic: chikungunya - Skin: HPV - Central Nervous System: rabies

What is a Virulence

How severe or harmful the disease is

Micro-Organisms in Biology - Bacteria— Key Features

🧠 Flashcard Questions for Bacteria (TEAS) 🔹 General Characteristics

• Q: Are bacteria prokaryotes or eukaryotes?

  • A: Prokaryotes (no nucleus).

• Q: What are the two types of Gram stains for bacteria?

  • A: Gram Positive (thick cell wall) and Gram Negative (thin cell wall).

• Q: What are the common shapes of bacteria?

  • A: Cocci (circle), Bacilli (rod), Staph (clusters), and Strep (chains).

• Q: What is the size range of bacteria?

  • A: 0.2 to 15 microns.

• Q: What is the difference between aerobic and anaerobic bacteria?

  • A: Aerobic bacteria need oxygen, anaerobic bacteria do not.

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🔹 Diseases Caused by Bacteria

• Q: Which bacterium causes strep throat?

  • A: Streptococcus.

• Q: What bacteria causes skin infections?

  • A: Staphylococcus aureus.

• Q: Name a bacterial cause of community-acquired pneumonia.

  • A: Mycoplasma.

• Q: Which bacteria causes tetanus?

  • A: Clostridium tetani (implied from "Tetanus").

• Q: What is chlamydia caused by?

  • A: Bacteria called Chlamydia.

Category	Details
Type	Prokaryote (no nucleus or membrane-bound organelles)
Size	0.2 – 15 microns
Gram Stain	- Gram Positive: thick cell wall- Gram Negative: thin cell wall
Shapes	- Cocci: spherical (circle) - Bacilli: rod-shaped - Staph: clusters - Strep: chains (line formation)
Oxygen Use	- Aerobic: needs oxygen - Anaerobic: does not need oxygen
Characteristics	Cell membrane with cell wall
Disease Examples	- Chlamydia- Community-acquired pneumonia (Mycoplasma)- Streptococcus (strep throat)- Staphylococcus aureus (skin infections)- Tetanus

✅ Important TEAS Exam Points (Additional)

Concept	Details
Prokaryotic Structure	Bacteria have cell membranes and walls but no nucleus.
Gram Stain Importance	Used to classify bacteria by cell wall thickness, guiding antibiotic use.
Bacterial Shape	Helps identify bacterial species in lab tests.
Aerobic vs Anaerobic	Oxygen requirement affects where bacteria can live and how they’re treated.

What is Gram Positive & Negative in Bacteria.

What type of toxins do they produce and how it works?

Gram Positive vs Gram Negative Bacteria What is Gram Staining?

• Gram staining is a laboratory technique used to classify bacteria into two major groups based on their cell wall structure.

• This classification helps identify the type of bacteria and guides treatment decisions.

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1. Gram Positive Bacteria

Produce

• Cell Wall: Thick layer of peptidoglycan (a strong, mesh-like polymer).

• Appearance After Staining: They retain the crystal violet stain used in the Gram stain procedure, so they appear purple or blue under a microscope.

• Other Features:

  • No outer membrane.

  • Generally more susceptible to antibiotics like penicillin.

• Examples: Streptococcus, Staphylococcus.

• Do not produce endotoxins (since they lack an outer membrane).

• Instead, many Gram-positive bacteria produce exotoxins.

• Exotoxins are proteins secreted actively by living bacteria.

• These exotoxins are often highly potent and can cause specific diseases or symptoms (e.g., the toxins from Clostridium botulinum or Staphylococcus aureus).

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2. Gram Negative Bacteria

Produce

• Cell Wall: Thin layer of peptidoglycan.

• Outer Membrane: Have an additional outer membrane containing lipopolysaccharides (LPS), which can act as toxins.

• Appearance After Staining: They do not retain the crystal violet stain but take up the counterstain (usually safranin), so they appear pink or red.

• Other Features:

  • Outer membrane can protect against some antibiotics.

  • Often more resistant to antibiotics.

• Examples: E. coli, Salmonella.

Produce endotoxins.

• Endotoxins are part of the outer membrane (specifically the lipopolysaccharide or LPS layer).

• These toxins are released when the bacteria die and the cell wall breaks down.

• Endotoxins can trigger strong immune responses, causing fever, inflammation, and even septic shock.

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Why Does It Matter?

• Knowing whether a bacterium is Gram positive or negative helps doctors choose the right antibiotics.

• The difference in cell wall structure affects how bacteria respond to drugs and how harmful they can be.

Bacteria Shapes

Cocci?

Bacilli?

Staph?

Strep?

Shapes

- Cocci: spherical (circle) - Bacilli: rod-shaped - Staph: clusters - Strep: chains (line formation)

Micro-Organisms in Biology - Fungi

What is chitin?

This slide is about Fungi, which are:

• Eukaryotes (meaning their cells have a nucleus and other organelles).

• Size ranges from 2 to 200 microns.

• Characteristics include:

  • Cell wall made of chitin.

  • Reproduce both sexually and asexually via spores.

• Disease examples caused by fungi:

  • Mycosis (general fungal infections).

  • Skin infections like Tinea (Ringworm, Athlete's Foot).

  • Infections of mucous membranes like Thrush.

  • Fungal infections in lungs and blood.

Chitin is a long-chain polymer of a sugar called N-acetylglucosamine, which is a derivative of glucose.

• It is a structural polysaccharide, meaning it provides strength and protection.

• Chitin is the main component of the cell walls of fungi, giving them rigidity and shape.

• It is also found in the exoskeletons of arthropods like insects, crustaceans (crabs, lobsters), and some other invertebrates.

• Chemically, it’s similar to cellulose (found in plants), but with nitrogen-containing groups.

Mycosis

• Superficial mycosis?

• Subcutaneous mycosis?

• Systemic mycosis?

Mycosis is a general term for fungal infections that affect humans or animals. It happens when fungi invade and grow on or inside the body.

There are different types of mycosis, depending on where the infection occurs:

• Superficial mycosis: affects the outer layers of the skin, hair, or nails (like athlete's foot or ringworm).

• Subcutaneous mycosis: affects deeper layers of the skin, often through cuts or wounds.

• Systemic mycosis: affects internal organs and can be serious, especially in people with weakened immune systems.

Micro-Organisms in Biology - Protozoa 原生动物

• Eukaryotes (meaning their cells have a nucleus)

• Size: 1 - 50 microns

• Characteristics: Unicellular organisms (single-celled)

Disease examples caused by protozoa:

• Malaria

• Giardiasis

Micro-Organisms in Biology - Animals

Flashcard Questions

Helminths:

1. Q: What are the three main types of helminths?

   • A: Roundworms (hookworms), flatworms (tapeworms), and flukes (liver flukes).

2. Q: What kind of diseases do helminths typically cause?

   • A: Gastrointestinal diseases.

3. Q: Are helminths eukaryotic or prokaryotic?

   • A: Eukaryotic.

Ectoparasites:

1. Q: Name four common ectoparasites.

   • A: Mites, fleas, bed bugs, ticks.

2. Q: What kind of reactions can ectoparasites cause on the skin?

   • A: Skin inflammation and allergic reactions.

3. Q: What disease can ticks transmit?

   • A: Lyme disease.

4. Q: Are ectoparasites endoparasites or ectoparasites?

   • A: Ectoparasites (live on the surface of the host).

This slide is about Animals (Helminths and Ectoparasites), which are:

• Eukaryotes (cells with a nucleus)

• Size: 3 millimeters to 10 meters

Characteristics:

• Helminths (Worms):

  • Round worms, such as hookworms

  • Flat worms, like tapeworms

  • Flukes, such as liver flukes

• Ectoparasites:

  • Mites

  • Fleas

  • Bed bugs

  • Ticks

Disease Examples:

• Helminths cause gastrointestinal (GI) diseases.

• Ectoparasites cause skin inflammation and allergic reactions.

• Ticks can transmit Lyme disease.

What is Vector from Infectious Disease

🔹 Active Vector

• The vector actively participates in the transmission.

• The pathogen develops or multiplies inside the vector.

• The vector may inject the pathogen into a new host during feeding (e.g., blood-sucking).

✅ Example:

• Mosquito (Anopheles): Transmits malaria by injecting Plasmodium parasites while feeding on blood.

• Tick: Transmits Lyme disease after the bacteria multiply inside its body.

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🔹 Passive Vector

• The vector does not play a biological role in the pathogen’s life cycle.

• The pathogen is simply carried on the body or surface of the vector.

• Transmission happens by contact, not by injection or feeding.

✅ Example:

• Housefly: Can carry bacteria or viruses on its legs from feces to food, causing diseases like typhoid or cholera.

• Cockroach: Passively carries pathogens on its body.

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🔁 Summary Table

Feature	Active Vector	Passive Vector
Role in pathogen life cycle	Pathogen multiplies or develops inside vector	No development inside vector
Transmission mode	Biting, injecting	Surface contamination
Example vector	Mosquito, tick	Housefly, cockroach
Example disease	Malaria, Lyme disease	Typhoid, food poisoning

Types of Light Microscopy Explained:

🔬 Key Terms:

• Magnification: The process of making something appear bigger.

• Resolution: The microscope's ability to distinguish fine details of a specimen.

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🔍 Types of Light Microscopy Explained: 1. Brightfield Microscopy

• Most common type.

• Light passes directly through the specimen.

• Image appears darker on a bright background.

• Used for stained or naturally pigmented samples.

Setup:

• Light → condenser lens → specimen → objective lens → viewer.

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2. Darkfield Microscopy

• Light is directed from the sides using a light stop.

• Only scattered light enters the objective lens.

• The specimen appears bright against a dark background.

• Ideal for live, unstained specimens (e.g., spirochetes).

Setup:

• Light → light stop (blocks central light) → only angled light hits the specimen → scattered light goes to the lens.

🔬 Electron Microscopes Overview

🔬 Electron Microscopes Overview

• Use beams of electrons instead of light.

• Provide much higher magnification and resolution than light microscopes.

• Allow us to view structures at the nanometer scale.

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📘 Types of Electron Microscopes 1. Transmission Electron Microscope (TEM)

• Views internal structures of cells or microorganisms.

• Electrons pass through a very thin sample.

• Produces 2D images with very fine detail.

✅ Best for:

• Seeing organelles inside cells.

• Observing viruses, cell membranes, etc.

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2. Scanning Electron Microscope (SEM)

• Views surfaces of samples.

• Electrons bounce off the surface, creating a 3D-like image.

• Shows texture and external structure in great detail.

✅ Best for:

• Examining bacteria surfaces, insects, materials, etc.

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🔁 Quick Comparison Table:

Feature	TEM	SEM
Image type	2D	3D-like
Focus	Internal structures	Surface structures
Sample requirement	Must be ultra-thin	Can be thicker
Resolution	Higher	Slightly lower than TEM