Notes, summaries, assignments, exams, and exercises for Biology for Baccalaureate

Disease Classifications

1. Duration

• Chronic: Appear slowly and last for a long time, sometimes forever. Example: Cirrhosis of the liver.
• Acute: Appear and end rapidly. Example: Measles.

2. Prognosis

• Benign: They rarely have complications and are easily cured. Example: Colds.
• Malignant: Very serious, cause significant damage, with poor prognosis. Examples: AIDS, cancer.

3. Time/Occurrence

• Endemic: Typical and permanent in a specific time and place. Examples: Malaria, cholera.
• Sporadic: Occasionally occur at any time and place. Examples: Hay fever, colds.

4. Causative Factor

• Environmental: Caused by several factors in the environment (radiation, cold, heat, chemicals, etc.). Examples: Freezing, heat stroke, skin burns.
• Congenital: Are inherited and manifest

Reproduction in Ferns (Pteridophyta)

Ferns exhibit a diplohaplontic life cycle, where the diploid sporophyte phase is predominant. The visible fern plant is the sporophyte. On the underside of the leaves, sori are formed, containing sporangia. Within these, stem cells produce spores via meiosis. These spores give rise to a tiny, heart-shaped prothallus.

The prothallus uses rhizoids to absorb nutrients from the soil. It develops antheridia, which produce flagellated antherozoids. These require water to swim toward the archegonium, where the oosphere is located. Fertilization occurs, forming a diploid zygote that develops into a new sporophyte.

Reproduction in Mosses (Bryophytes)

Mosses remain dependent on an aqueous medium for reproduction. Their...

Catabolic and Anabolic Metabolism

Catabolic metabolism is oxidized when it loses electrons. It is a set of molecular processes that transform complex molecules into simpler ones. The energy molecule ATP stores energy. Energy is released during the oxidation of molecules, especially if O₂ is the ultimate acceptor (aerobic) or if another acceptor is used (anaerobic). Fermentation is the incomplete oxidation of energy molecules. For example, glucose activates Bacillus, and the initial product in the muscles is lactic acid. Alcohol fermentation starts with glucose in yeast, and the final product is ethyl alcohol. Putrefaction of proteins into simpler molecules is performed by some organisms.

Anabolism is a set of reduction reactions in which it is...

Biotechnology and Genetic Innovations

Biotechnology

A set of techniques that leverage biochemical transformations to improve the performance of certain food processes, create substances with therapeutic activity, or resolve environmental alterations.

Genetic Engineering

Technology involving the manipulation and transfer of DNA from one organism to another, enabling the creation of new lineages of a given species.

Transgenic Organism

Hereditary material that has been modified by inserting a foreign gene or deleting one of its own.

Creating Transgenic Animals

The most commonly used technique is microinjection. It consists of obtaining the fertilized egg of the animal before it splits, and injecting DNA (containing the desired gene) into it.

Stem Cells

Embryonic...

Biomolecules: Nucleic Acids

Nucleoside: Union of a nitrogenous base with a pentose sugar.

Nucleotide: Union of a nucleoside with a phosphoric acid group.

Nucleic Acid: Polymer made of hundreds or thousands of nucleotides.

Functions: Genetic information storage, transmission, transcription, and translation.

Difference Between DNA and RNA

• Sugar: Deoxyribose (DNA) vs. Ribose (RNA)
• Bases: Adenine (A), Guanine (G), Cytosine (C), Thymine (T) in DNA vs. Adenine (A), Guanine (G), Cytosine (C), Uracil (U) in RNA
• Structure: Generally long double-stranded chains in DNA vs. Generally shorter single-stranded chains in RNA (although RNA can have loops and folds, and some viruses have double-stranded RNA)
• Stability: DNA has no free OH group at the 2' carbon, which

Cytoplasm:

The cell space between the nuclear envelope and plasma membrane. Comprising cytosol, cytoskeleton, and organelles.

Cytosol:

The internal environment of the cytoplasm (75-85% water). It performs the synthesis of ribosomes and protids (enzymes, small molecules, or proteins). It forms filaments of the cytoskeleton. Due to the presence of many enzymes, there are numerous metabolic reactions.

Cytoskeleton:

In eukaryotes, it forms a network of protein filaments. Features:

• Maintaining the shape of the cell and the possibility of changing it.
• The possibility of moving the cell.
• Contraction of muscle.
• Transport and organization of organelles.

Microfilaments:

Actin filaments are the main components of the cytoskeleton. Usually, they partner with other...

Intercellular Cell Junctions

There are three primary types of intercellular junctions:

• Desmosomes: Specialized junctions that bridge large intercellular spaces. They anchor cells without preventing intercellular space passage. They consist of two discoidal structures linked to the cytoskeleton by keratin filaments, connected by transmembrane proteins.
• Tight Junctions: These eliminate intercellular space. They are formed by protein molecules arranged in transmembrane rows that seal plasma membranes together, strengthened by filamentous proteins.
• Gap Junctions: These maintain small intercellular spaces that allow communication and the exchange of cytoplasmic molecules. They consist of two connexons (tubes made of transmembrane proteins) that cross

Biological Macromolecules: Proteins, Enzymes, and Nucleic Acids

Proteins: Structure and Function

Proteins are essential biological macromolecules (biomolecules) composed primarily of Carbon (C), Hydrogen (H), Oxygen (O), and Nitrogen (N). They are polymers formed by the linkage of subunits called amino acids (AAs).

Amino Acid Composition

Each amino acid consists of a central carbon atom bound to four groups:

• A carboxyl group (COOH)
• An amino group (NH₂)
• A hydrogen atom (H)
• A variable side chain or radical (R group)

There are 20 distinct amino acids that form proteins. These subunits are linked together by a peptide bond, which forms through a dehydration reaction between the amino group of one AA and the carboxyl group of another, releasing a molecule...

Part A: Multiple Choice

• What is the monomer of a protein?
  Answer: c) Amino acid
• A scientist adds Lugol's iodine solution to an unknown clear liquid, and it instantly turns deep blue-black. What biomolecule is present?
  Answer: b) Starch
• Why does an enzyme cease to function after being exposed to an extremely high temperature?
  Answer: c) The enzyme denatures, altering the shape of its active site.
• Which of the following functions as a micronutrient in the human body?
  Answer: b) Iron (Mineral)

Part B: Structure Identification & Fill-in-the-Blanks

1. Peptide bond
2. Protein
3. Starch
4. Glycogen

Part C: Metabolic Roles and Protein Folding

While carbohydrates provide the raw chemical energy (calories) for the body, micronutrients (vitamins and minerals) act as essential...

Apoptosis

“A pattern of cell death in which cells activate enzymes that degrade the cell's own nuclear DNA and nuclear and cytoplasmic proteins.”

Causes

I. Physiologic (Most Common)

• Programmed destruction of cells during embryogenesis.
• Hormone-dependent involution of tissues in the adult (e.g., endometrium).
• Cell loss in proliferating cell populations, such as epithelial cells in intestinal crypts.
• Death of host cells after serving their useful purpose (e.g., neutrophils in an acute inflammatory response).

II. Pathologic

• DNA damage due to radiation, cytotoxic drugs, and hypoxia.
• Accumulation of misfolded proteins causing endoplasmic reticulum (ER) stress (e.g., degenerative diseases of the CNS).
• Cell death associated with viral infections, such as