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

Core Terminology in Classical Genetics

• Character (Trait): An inherited attribute of an individual.
• Gene: The fundamental unit of heredity responsible for a character.
• Alleles: The different variations or forms that a gene can take.
• Homozygous: An individual possessing two identical alleles for a specific gene.
• Heterozygous: An individual possessing two different alleles for a specific gene.
• Genotype: The specific set of genes an individual possesses.
• Phenotype: The set of observable, hereditary traits expressed by an individual.

Allelic Expression and Inheritance Patterns

• Dominant Factor (Allele): The allele that is phenotypically expressed in both homozygous and heterozygous individuals.
• Recessive Factor (Allele): The allele whose phenotypic expression

The Cells and Tissues of Plants

Plant Cell: Plant cells have eukaryotic cell structures except for the animal centrosome and possess a cell wall surrounding the membrane. They have chloroplasts and vacuoles.

Cell Types

Parenchymal Cells: These cells secrete substances and store hormones. They can undergo differentiation to perform specific functions, such as tracheids, which die and become woody vessels to circulate crude sap.

Simple and Complex Tissues

Tissues are groups of cells that perform a specific activity. They are classified according to the number of cell types (one or more) into simple and complex tissues.

• Simple Tissues: Parenchyma, collenchyma, and sclerenchyma.
• Complex Tissues: Formed by different cell types performing various functions,

Fixism

This theory proposes that species do not change; they remain unchanged from their creation. Linnaeus was a proponent of this thought.

Catastrophism

Georges Cuvier proposed that land disasters had destroyed existing species, leading to the creation of new species.

Neutral Theory

This theory posits that chance variations occur in populations, where a mutant gene can be dispersed without any selective advantage.

Punctuated Equilibrium

This theory suggests that the absence of intermediate steps in the fossil record is not due to incompleteness, but rather that evolution sometimes occurs in "leaps."

Evidence of Evolution

• Morphological: Studying comparative anatomy helps to understand the similarities and differences of the same organ in different

Invertebrate Excretory Systems (Protonephridia): These are found in animals with no coelom, such as flatworms. They consist of highly branched tubes that end in a few cells with cilia (flame cells) or flagella (solenocytes). Both cilia and flagella are located in the lumen of the tube, and their movement causes the continuous elimination of waste substances. (Metanephridia): This system occurs in coelomates (annelids, mollusks, etc.). It is made up of a coiled tube surrounded by a capillary network, with two openings: the external (nephridiopore) and internal (nephrostome), which opens into the coelomic cavity. Inside the metanephridia, reabsorption occurs for compounds that are still useful, while waste substances are expelled outside through...

Special Types of Cell Division

• Budding: Casts asymmetric cytoplasmic material; the daughter cell emerges as a bud from one side of the mother, such as in yeast or sponges.
• Sporulation: Several successive mitoses occur without cytokinesis; multinucleate cells are formed, for example, in fungi and protozoa.

Meiosis

To condense, look better.

Meiosis I

Stages of Prophase I

It is the most complex stage, with five sub-phases:

1. Leptotene: Chromosomes condense to become visible by light microscopy. Each is composed of two chromatids.
2. Zygotene: Homologous chromosomes pair up until they are completely aligned along their length. This pairing is called synapsis and occurs through a protein structure called the synaptonemal complex.
3. Pachytene: Crossover (chromatid

Linnean Binomial Nomenclature

Linne-binomial nomenclature (genus-species) in the animal kingdom: chordate phylum, class, mammals, primate order, family Hominidae, genus Homo, Homo sapiens species.

Arthropods

3 main groups of animals: arthropods: exoskeleton made of chitin, articulated appendages. Insects are an example.

Mollusks

Mollusks: shell, visceral mass, and mantle body (head and foot), e.g., snails.

Chordates

Chordates: Notochord and cephalization. Includes vertebrates: fish and tetrapods (amphibians, birds, mammals).

Animal Nutrition Strategies

• Filter feeders: Consume organic particles or organisms in suspension (e.g., zebra mussels).
• Substrate feeders: Live permanently in their food source (e.g., earthworms).
• Fluid feeders: Feed exclusively on

Sexual Reproduction

• Viviparous: blue whale, camel, human, zebra, manatee, rabbit
• Oviparous: peacock, sea turtle, hummingbird, crocodile, quail, duck
• Ovoviviparous: kangaroo, frog, tropical fish (guppy, xiphophorus), weasel, lizard

Asexual Reproduction

• Vegetative Propagation: strawberry, rose, pineapple, sweet potato, garlic, moss
• Budding: anemone, coral, bryozoan, sponge, yeast (e.g., Penicillium), medusa
• Sporulation: fungi, lycopodium, green algae, amoeba, wheat rust
• Fragmentation: planaria, brown algae, coral, pink fungus, lichen, worm

Leaf Morphology and Classification

Leaf Venation Types

• Uninervate: Single prominent vein
• Parallelinervate: Veins run parallel
• Curvinervate: Veins curve
• Pinnately Nerved: Veins branch off a central midrib like a feather
• Palminervate:

Excretion is the elimination of waste products (such as carbon dioxide and nitrogenous wastes) and is a crucial part of the broader processes aimed at maintaining homeostasis, which is essential for an organism's survival. Homeostasis is the process of maintaining constant internal conditions. The two pillars that maintain homeostasis in animals are excretion and osmoregulation.

Excretory Structures

Excretory systems use tubes to collect fluid from the blood, hemolymph, or extracellular fluid to adjust its composition through the reabsorption of useful substances and the active secretion of waste products.

• Sponges, Cnidarians, Nematodes, and Echinoderms: These organisms lack specialized excretory structures and eliminate waste through diffusion

Cell Membrane Transport

Diffusion

Some substances move through diffusion inside and outside cells. Diffusion is a physical process based on random movement. The kinetic energy associated with the random motion causes diffusion, the net movement of particles (atoms, ions, and molecules) from a region of high concentration to a region of low concentration, resulting in a uniform distribution.

Conveyor-Mediated Transport

For the transport of ions and nutrients, conveyor systems (permease proteins) evolved early in the origin of cells. This transfer of solutes by membrane proteins is called carrier-mediated transport. There are two variants: facilitated diffusion (along the concentration gradient or electrochemical-chemical-concentration difference,...

Eukaryotic Cell Organelles and Functions

Eukaryotic cells, found in animals, plants, fungi, and protists, contain specialized structures called organelles that perform essential life functions. Below is a detailed look at the key components found in animal and plant cells.

Animal Cell Organelles

Nucleus: The Control Center

• Nickname: The Control Center
• Function: Holds the DNA (genetic material).
• Parts: The Nucleolus is the dark spot within the nucleus that helps manufacture ribosomes.

Ribosomes

• Function: Responsible for protein synthesis (making proteins).
• Note: Ribosomes are found in all cells, both Prokaryotic and Eukaryotic.

Endoplasmic Reticulum (ER): The Roads

• Nickname: Roads (Internal Delivery System)
• Function: Serves as the internal delivery system