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

The Cell Cycle

The cell cycle consists of two main phases: interphase and mitosis (M phase) [3].

Interphase

Interphase is further divided into three phases:

1. G1 phase (Gap 1): During this phase, the cell grows in size and carries out normal metabolic activities [4].
2. S phase (Synthesis): In this phase, DNA replication and chromosome duplication occur [4].
3. G2 phase (Gap 2): The cell continues to grow and prepares for cell division [4].

Mitosis (M phase)

Mitosis is the actual phase of cell division and is divided into four stages:

1. Prophase: Chromosomes condense, the nuclear envelope and nucleolus disappear, and spindle fibers start to appear [4].
2. Metaphase: Chromosomes align at the equatorial plate [4].
3. Anaphase: Centromeres divide, and chromatids move towards

Basic Concepts

Characteristics of Living Things

• Movement - motion where the organism will go from one place to the other
• Responsiveness - how any organism reacts
• Growth - an organism's ability to get bigger
• Reproduction - ability of an organism to produce offspring
• Respiration - the ability of an organism to gain oxygen from food
• Digestion - ability of an organism to break down food
• Absorption - ability of an organism to take in nutrients
• Circulation - ability of materials to go through the body
• Assimilation - food is taken in and changed to something essential
• Excretion - ability of our bodies to remove waste

Homeostasis and Regulation

Eyes

Orbital Hematoma (Black Eye)

An orbital hematoma, commonly known as a black eye, results from a blow to the area surrounding the eye, which causes capillary bleeding.

Signs & Symptoms:

• Noticeable swelling and discoloration around the orbit.

Orbital Fracture

An orbital fracture is caused by a direct blow to the eyeball, forcing it posteriorly. This action compresses the orbital fat until a blowout rupture occurs to the floor of the orbit.

Signs & Symptoms:

• Diplopia (double vision)
• Restricted eye movement
• Downward displacement of the eye

Hyphema

A hyphema is a collection of blood in the anterior chamber of the eye, typically resulting from blunt trauma to the eye. This is a major eye injury that can lead to serious problems.

Signs & Symptoms:

Characteristics of Living Organisms

• Respiration and Metabolism

  Cells carry out chemical reactions, such as respiration, to produce energy.

• Reproduction

  The process of creating new organisms, which can be sexual or asexual.

• Nutrition

  Chemical substances used for growth, repair, and other vital functions.

• Growth

  An increase in the size and number of cells.

• Homeostasis

  The ability to regulate the internal environment to maintain it constant or within certain limits.

• Excretion

  The removal of waste products generated by metabolism.

• Movement

  The ability to change position.

• Sensitivity

  The ability to detect changes in the external environment.

Comparing Animal and Plant Cells

Animal Cell Structure

Key components include the nucleus, vacuole, cell membrane, and granular... Continue reading "Fundamental Characteristics of Life and Cell Biology" »

Understanding Heredity

Traits

Traits are characteristics present in an organism that can be inherited by its offspring.

Genes and Alleles

A gene is a section of DNA containing information about a specific trait and controlling that trait. Alleles are the different alternatives that a gene controlling a particular trait can have.

Homozygous and Heterozygous

• Homozygous: If the two alleles of a specific gene are identical (e.g., AA or aa), the individual is homozygous or pure for that trait.
• Heterozygous: If the two alleles of a specific gene are different (e.g., Aa), the individual is heterozygous or hybrid for that trait. (A is the dominant allele and a is the recessive allele).

Genotype and Phenotype

• Genotype: An organism's set of genes.
• Phenotype: The

Understanding Overdentures

An overdenture is a complete or removable partial denture whose base covers one or more retained teeth and/or one or more dental implants. It is designed to provide enhanced stability, retention, and support, and typically requires a retentive system.

Key Features and Support Options

Overdentures offer a removable prosthetic option, utilizing remaining natural teeth or supported by dental implants.

Advantages Over Conventional Dentures

• 1. Alveolar Bone Maintenance: Retained roots convert compressive forces into tractional forces, helping to preserve alveolar bone.
• 2. Increased Masticatory Forces: Overdentures significantly improve chewing efficiency and force.
• 3. Enhanced Tactile Discrimination: The periodontal ligament

The Nervous System

Cranial Nerves

Twelve pairs of cranial nerves enter and exit the brain, comprising sensory, motor, and mixed types. They innervate the head, upper torso, and some internal organs. Some cranial nerves are associated with the autonomic nervous system. Along their pathways, ganglia—groups of neuronal cell bodies—can be observed.

Spinal Nerves

Thirty-one pairs of mixed spinal nerves emerge from the spinal cord. Each nerve originates as two distinct roots—dorsal and ventral—which merge to form a single nerve cord. Sensory neurons enter the spinal cord through the dorsal root, while motor neurons exit through the ventral root.

The Autonomic Nervous System

The autonomic nervous system (ANS) regulates involuntary bodily functions.... Continue reading "The Nervous and Endocrine Systems: A Comprehensive Overview" »