Notes, summaries, assignments, exams, and exercises for Biology for Other courses

Introduction to Enzymes

Enzymes are biological macromolecules, primarily proteins, that act as catalysts. They are essential for life, facilitating and accelerating chemical reactions within and outside cells without being consumed or permanently altered in the process.

• Enzymes significantly accelerate the rate of metabolic reactions.
• They are not consumed or changed during the reaction; an enzyme acts on a substrate and then releases the product, remaining available for further reactions.

Enzyme-Substrate Interaction

The substance upon which an enzyme acts is called the substrate. The substrate binds to a specific region on the enzyme known as the active site. This active site is composed of two main parts:

• Binding Site: Formed by specific amino

Foods Discouraged

• Kitchen and table salt: salt, iodized salt, sea salt, celery salt.
• Meat: salted, smoked and cured.
• Smoked and dried fish, caviar.
• Sausages in general.
• Cheeses in general (Burgos types are allowed, Villalon).
• Bread and biscuits with salt (except for minor amounts of 50 g).
• Olives.
• Soup, instant mashed, diced, chips.
• Packaged vegetable juice.
• Oleaginous fruits, salty.
• Confectionery industry.
• Salted butter, margarine and salt.
• Sparkling water, carbonated beverages in general.
• Seasonings: salt, mustard, pickles, ketchup, meat tenderizer.
• Preserved foods in general.

Foods Allowed

• Meat, poultry.
• Viscera: tongue, kidneys, liver.
• Fresh fish freshwater or sea.
• Eggs.
• Milk, yogurt, Petit-suisse, curd.
• Cheese without salt.
• Unsalted bread and biscuits (up to

Biology Study Summary:

Scientific Method and Measurement

• Hypothesis-driven science: Starts with a question or hypothesis. A hypothesis is a tentative, testable explanation or prediction based on observations. A theory has been repeatedly tested and consistently supported.
• Discovery science: Focuses on observations and data ("What do we observe?").
• The meniscus: The curved line on a graduated cylinder used to measure volume. Read from the bottom of the curve (e.g., 5 mL is just below the 5).

Chemistry of Life and Solutions

• pH: A measure of acidity or basicity in a solution.
• Acid: Has an increased concentration of H⁺ ions and decreased OH^- ions.
• Base: Has an increased concentration of OH^- ions and decreased H⁺ ions.
• Buffer: Resists a change in pH.
• Polarity:

Renal System Functions (GI-A-W-E-T-B-E-D)

• G: Acid-base balance
• I: Water balance
• A: Electrolyte balance
• W: Toxin removal
• E: Blood pressure (RAAS)
• T: Erythropoietin
• B: Vitamin D activation

Urine Formation

• Glomerular filtration: Filters water and small solutes.
• Tubular reabsorption: Returns substances to the blood.
• Tubular secretion: Adds wastes to tubules.
• Excretion: 1–2 L/day; ≥30 mL/hr minimum.

Key Renal Hormones

• ADH: Water reabsorption.
• Aldosterone: Increases Na⁺ reabsorption.
• ANP: Decreases Na⁺ and water reabsorption.

Urolithiasis (Kidney Stones)

Types: Calcium (alkaline urine), Uric acid (acidic urine; gout), Struvite, and Cystine.

Signs/Symptoms: Renal colic, sudden flank to groin pain, nausea/vomiting, sweating, tachycardia, and hematuria.

Treatment:...

Cancer Stem Cells vs. Normal Stem Cells

Both normal stem cells and cancer stem cells (CSCs) share the ability to self-renew through asymmetric division, allowing one daughter cell to remain a stem cell while the other differentiates. They both generate heterogeneous populations of mature cells: normal stem cells produce tissue-specific cell types, while CSCs produce diverse tumor cells. Both rely on similar regulatory signaling pathways such as Wnt, Notch, and Hedgehog, but these pathways are tightly controlled in normal stem cells and dysregulated in CSCs, promoting tumor formation. Both exist as rare subpopulations within tissues, depend on signals from their niche, and can remain quiescent for long periods. CSCs, however, show enhanced resistance...

Animal Eukaryotic Cells and Organelles

• Nucleus: Holds genetic material. Protected by a double membrane that separates it from the cytoplasm.

• Vacuoles: Small sacs that store different substances.

• Lysosomes: Made by the Golgi apparatus; digest materials inside the cell.

• SER (Smooth Endoplasmic Reticulum): Produces lipids and helps remove toxic substances.

• Mitochondria: Have two membranes; break down glucose to release energy (cellular respiration).

• Cytoplasm: Jelly-like fluid with the cytoskeleton that supports and gives shape to the cell.

• RER (Rough Endoplasmic Reticulum): Stores and transports proteins made by ribosomes attached to it.

• Ribosomes: Smallest organelles, no membrane; make proteins, free or attached to RER.

• Cell membrane: Made of lipids

Atrial Natriuretic Hormone (ANH)

Atrial natriuretic hormone (ANH) is released by the atria of the heart in response to elevated blood pressure or volume. It lowers blood pressure by encouraging salt excretion in the urine (natriuresis). It also lowers systemic vascular resistance by widening blood vessels.

ANH decreases the kidneys' ability to reabsorb water and salt by blocking the release of renin and aldosterone. To further lessen water retention, it also inhibits the release of antidiuretic hormone (ADH). This combined action reduces blood pressure and volume. By opposing the renin-angiotensin-aldosterone system, ANH preserves fluid equilibrium. It is essential for kidney and heart health. Atrial stretch is what causes the release of ANH....

Oral Anatomy and Dental Structures

• Mouth (Boca): Another term for the oral cavity.
• Oral Cavity (Cavitat Oral): Another name for the mouth.
• Teeth (Dientes): Hard, white, enamel-covered structures used to chew and bite food.
• Tongue (Lengua): A muscle located at the base of the oral cavity used to speak and eat.
• Tonsils (Amígdalas): Structures located at the left and right sides of the palatoglossal arch.
• Uvula: A cone-shaped tissue that hangs down from the soft palate.
• Hard Palate (Paladar Duro): The bony front portion of the roof of the mouth.
• Soft Palate (Paladares Blandos): A fibrous and muscular soft tissue that comprises one-third of the roof of the mouth.
• Upper Lip (Labio Superior): A structure made of soft, pink tissue close to the nose.
• Lower

What is an Operon?

An operon is a group of genes that are linked together and share a common promoter, allowing them to be transcribed together as a single mRNA molecule. This arrangement enables the coordinated expression of multiple genes that often work together in a specific biological process.

The Lac Operon Mechanism

The lac operon is a crucial system in bacteria that helps them break down lactose. It includes three main genes: lacZ, lacY, and lacA.

• lacZ: Produces an enzyme called beta-galactosidase, which splits lactose into glucose and galactose.
• lacY: Makes lactose permease, which helps transport lactose into the cell.
• lacA: Responsible for thiogalactoside transacetylase, which detoxifies certain compounds.

When lactose is absent, a repressor