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

Animal Sensory Organs

The Lateral Line System

The lateral line is a specialized sensory organ found in fish and amphibian larvae. It can be identified as longitudinal lines on each side of the animal's body. These lines are formed by a succession of small pores that cross the scales and connect with a long, fluid-filled tube running beneath the skin along the animal's flanks. The inner tube is lined with hair cells, capable of capturing even the smallest water vibrations.

Facial Pits

The facial pit is a thermosensitive organ found in some snakes, such as rattlesnakes. It consists of two structures located between the eyes and mouth. These pits contain receptors capable of capturing infrared radiation, i.e., the heat emitted by other bodies. This...

Core Concepts in Biotechnology and Genetics

Genetic Code

The genetic code is the set of rules by which information encoded in messenger RNA (mRNA) sequences is translated into amino acid sequences during protein synthesis. It dictates which amino acids correspond to each codon, allowing them to join together in the correct position to form a protein.

Biotechnology

Biotechnology involves the use of living organisms, or parts of organisms, or modified products derived from them, to improve plants or animals, or to develop microorganisms for specific objectives.

Plasmids

Plasmids are circular DNA molecules, independent of the chromosomal DNA, that often carry genetic information useful to the host organism, typically found in bacteria and yeasts.

Bacteriophage

Asexual Reproduction in Cormophytes

Asexual reproduction in cormophytes involves specific vegetative organs such as stolons, rhizomes, tubers, and bulbs.

• Runners: These are side branches emerging from the base of the stems with horizontal growth. Roots emit buds, giving rise to new independent individuals.
• Rhizomes: Underground stems that grow horizontally in the soil and accumulate reserve substances. Ground stems can emerge from buds, eventually taking root and separating from the main rhizome.
• Tubers: Very enlarged underground stems that store food. They can be separated from the main plant to form separate plants.
• Bulbs: Underground stems that are more or less spherical, with fleshy, layered storage. Smaller bulbs are often formed with buds

Item 14. Physical Agents: Thermal Environment

Introduction

Thermal environment refers to environmental conditions including:

• Temperature
• Humidity
• Physical activity

Homeotherms

Homeotherms maintain internal temperature within very narrow ranges.

• Danger: Heat stress
• Heat discomfort
• Comfort
• Discomfort from cold
• Danger: Hypothermia

Thermal Equilibrium

Thermal equilibrium between body and environment involves mechanisms of thermoregulation.

Mechanisms of Thermoregulation

Q = M ± R ± C - E

• Q: Heat generated or heat buildup
• M: Metabolic activity
• R: Radiation exchange
• C: Exchange by convection
• E: Heat lost by evaporation

Radiation Exchange (R)

Heat exchange that originates between two solid bodies in proximity.

Exchange by Convection (C)

Mechanism by which the body exchanges...

A gene is the carrier of an inherited feature that is passed from generation to generation.

Alleles are possible alternatives for a character. Alleles stand at the same site on two chromosomes in an individual, one from each parent. Alleles are equal when it is said that the individual is homozygous or pure-bred for the character. If different, they are heterozygous or hybrid.

A dominant allele is the character that is always represented (capital letters).

A recessive character emerges only in homozygous individuals (lowercase).

Genotype is the joint of the genes, half from one progenitor and the other half from the other.

Phenotype is the set of characters that manifests externally. This is particular, but the genotype influences the environment....

Apoptosis: Cellular Suicide

Apoptosis, or programmed cell death, is a crucial mechanism in multicellular organisms. It plays a vital role in development, removing unnecessary cells during embryonic stages (e.g., interdigital tissue), and in adulthood, eliminating damaged or potentially harmful cells. This process involves a series of changes leading to cell death. The cell shrinks, loses water, and forms bubble-like protrusions. The nucleus fragments, and the resulting apoptotic bodies are ingested by neighboring cells. Apoptosis is triggered by signals that activate endonucleases, which in turn produce lethal proteins, hydrolases, and proteases.

The Interphase Nucleus

The interphase nucleus houses the genetic material and controls all cellular...

The Fungi Kingdom

The fungi are a large group of organisms; they may be unicellular or multicellular.

Characteristics of Fungi

• They are organisms without chlorophyll.
• They reserve substances as drops of oil.
• They are unicellular or multicellular.
• Most contain a substance called chitin, a nitrogen polysaccharide found in the exoskeleton of arthropods (insects).
• They have a cell wall composed of cellulose.
• They are heterotrophs.

Fungi have a large number of species. Many are saprophytes, feeding on dead remains, helping animals and plants decompose. Many fungi are parasites, living on higher organisms. There are other fungi that live on animals; for example, fungal infections like athlete's foot and ringworm are caused by fungi.

Reproduction of Fungi

Fungi...

What Are Secondary Metabolites?

Secondary metabolites, also known as specialized metabolites, secondary products, or natural products, are organic compounds produced by various life forms, including bacteria, archaea, fungi, animals, and plants. These compounds are not directly involved in the organism's normal growth, development, or reproduction. Instead, they primarily mediate ecological interactions, often providing a selective advantage that enhances survivability or fecundity.

Ecological Roles and Specificity

Specific secondary metabolites are frequently restricted to a narrow range of species within a particular phylogenetic group. They play a crucial role in plant defense against herbivory and other interspecies defenses. Humans utilize...

1: Carcinoma (Flat) and Sarcoma (Round)

Cancer Cell Characteristics and Hallmarks

Carcinoma (flat) and sarcoma (round) both arise from cancer in mesenchymal cells. The Hallmark of Cancer concept examines cancer at the cellular level, recognizing that cancer results from numerous different mutations.

Tumor Suppressor Proteins

A key example is the p53 tumor suppressor protein. Tumor suppressors act as the cell's "brakes" because they control cell division. When cancerous, these proteins often show a loss of function due to mutation, resulting in fewer active target proteins.

• CO2 Removal: Carbon dioxide (CO2) is the easiest molecule to remove from the cell due to its small molecular size.
• Structural Impact: Tumor suppressors affect tertiary/quaternary

Key Concepts in Enzymes, Cellular Respiration, and Genetics

1. Free Energy Curve

In a catalyzed reaction, the enzyme lowers the activation energy required for the reaction, making it proceed more quickly. The free energy curve for the catalyzed reaction is shifted to the left compared to the uncatalyzed reaction.

2. Components in a Chemical Reaction

• Reactants: A and B
• Products: C and D (catalyzed)

3. Factors Affecting Enzyme Function

• Temperature: Enzymes have an optimal temperature; deviation can denature them.
• pH: Enzymes function best within a specific pH range.
• Substrate Concentration: Up to a point, increasing substrate concentration increases enzyme activity.

4. Definition of an Enzyme

Enzymes are biological catalysts that accelerate chemical reactions...