Notes, summaries, assignments, exams, and problems for Biology

Tissue

Tissue: is formed of cells of a similar type that work together to carry out specific functions. Most tissue cells are held together by their own intercellular substances. The human body has four different tissue groups:

Connective Tissue

Connective tissue proper: It surrounds and connects organs and has a gel-like intercellular matrix. Ex: Tendons and ligaments.

Adipose tissue: Stores lipids for protection and energy reserves, using cells called adipocytes.

Cartilaginous tissue: It has a solid, elastic intercellular matrix and cells known as chondrocytes.

Bone tissue: Its rigidity allows it to support the body, along with cartilage.

Blood tissue: It is responsible for the transport of nutrients, hormones and waste, as well as for protecting... Continue reading "Human Tissues, Organs and Body Systems" »

Key Terms in Genetics

DNA: deoxyribonucleic acid, substance that carries genetic information in a cell.

Protein: organic compound that consists of long chains of molecules and is an essential part of living things.

Genetic code: set of instructions in a gene that tells a cell how to make a specific protein.

Genome: set of genes in an organism.

Genetic engineering: manipulation of genetic material to change the traits of an organism.

Biotechnology: biological techniques to create improved products for human consumption.

Genes and Their Role

Genes: are located in the chromosomes and are the basic unit of inheritance that carry genetic information. Genes consist of DNA, the molecule that gives cells and all organisms biological information.

Cell Cycle

Pharyngeal Arches

• First Arch: Mandibular nerve, Meckel's cartilage, muscles of mastication, tensor tympani, mylohyoid, anterior belly of the digastric
• Second Arch: Facial nerve, Reichert's cartilage (hyoid bone), muscles of facial expression, posterior belly of the digastric, stylohyoid, stapedius
• Third Arch: Glossopharyngeal nerve, hyoid bone, stylopharyngeus muscle
• Fourth Arch: Vagus nerve, laryngeal cartilages, soft palate muscles (except tensor veli palatini), pharyngeal muscles (except stylopharyngeus)
• Fifth Arch: Vagus nerve, no specific structure, arytenoid muscle
• Sixth Arch: Vagus nerve (recurrent laryngeal), no specific structure, intrinsic muscles of the larynx (except cricothyroid and arytenoid)

Pharyngeal Pouches

• First Pouch: Auditory tube

Microorganisms: Definitions and Characteristics

Place the correct number in the boxes to match the organism with its definition.

1. Fungus: A spore-producing organism that absorbs nutrients from the environment.
2. Protist: Any eukaryotic organism that is not an animal, plant, or fungus.
3. Bacteria: A prokaryotic organism with peptidoglycan in its cell walls.
4. Archaea: A prokaryotic organism without peptidoglycan in its cell walls.
5. Virus: A microscopic particle that cannot replicate on its own.

Understanding Hosts in Biology

A host is:

• An infected protein
• A prokaryotic organism
• A living thing that a virus or parasite uses for shelter
• A cell destroyed by a virus

Extreme Habitats of Archaea

Label these extreme habitats of Archaea with the correct names from the box:... Continue reading "Microorganisms, Reproduction, and Species Classification" »

Structural Components of Viruses

• Capsid: Protein shell that encloses a viral genome; may be rod-shaped, polyhedral, or more complex in shape
• Viral envelopes: Membrane that cloaks the capsid that in turn encloses a viral genome

Obligate Intracellular Parasites

Viruses can only reproduce within host cells because they lack metabolic enzymes, ribosomes, and other equipment for making proteins.

• Identifying host cells: "Lock and key" fit between proteins on the outside of the virus and specific receptor molecules on the host's surface (which originally evolved for functions that benefit the host).

Bacterial Defenses Against Phages

While phages have the potential to wipe out a bacterial colony in just hours, bacteria have defenses against phages:

• Natural

Applications and Skills

Comparison of Water and Methane Thermal Properties

Water and methane are small molecules with similar covalent structures, yet their physical properties differ significantly due to water's polarity.

Since water is polar, it has stronger intermolecular attraction (hydrogen bonds) and therefore has a much greater specific heat capacity, latent heat of vaporization, melting point, and boiling point.

Water as a Coolant in Sweat

• Water is essential to living organisms.
• Water

Evolutionary Theories

Punctuated Equilibrium vs. Neo-Darwinism vs. Neutralism

• All three theories propose evolutionary change.
• Punctuated Equilibrium: Evolutionary changes occur rapidly and abruptly.
• Neo-Darwinism: Evolutionary changes occur gradually over time.
• Neutralism: Most mutations have no effect on natural selection.

Barriers to Genetic Isolation

• Geographical
• Sexual
• Physiological
• Chromosomal
• Ethological

Ecological Concepts

Abiotic and Biotic Factors

• Abiotic Factors: Non-living factors that affect ecosystems (e.g., temperature, pH, wind)
• Biotic Factors: Living components that affect ecosystems (e.g., disease, predation, competition)

Biomass

- Total dry weight of organic matter in organisms or ecosystems. - Includes carbohydrates, proteins, etc.

Ecosystems

Water: The Essential Solvent

Water constitutes approximately 80% of the human body and plays a crucial role in biological systems.

Role of Water as a Solvent

Water is an important solvent, a liquid in which substances (or solutes) are dissolved, forming a solution. In a solution, the solvent is typically present in a greater amount than the solute.

Metabolic reactions, which are vital for life, can only take place if the chemicals reacting are dissolved in water.

Other Vital Functions of Water

Water is also essential for other reasons, such as being the primary component of plasma, the liquid part of blood, facilitating transport throughout the body.

Carbohydrates: Energy & Structure

Carbohydrates include starches and sugars, and are composed of... Continue reading "Fundamental Biological Molecules: Water, Carbohydrates, Lipids, Proteins, DNA" »