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

1. Interaction and Coordination

The basic path of a nerve impulse from stimulus to response is:

1. A stimulus occurs.
2. Sensory receptors detect the stimulus.
3. Sensory neurons receive the information and transmit it to the central nervous system (CNS).
4. The CNS receives the information and a response is decided.
5. Motor neurons transmit the response to the effectors.
6. Effectors carry out the response. An effector can be a muscle or a gland.
7. The response is given. There are two types: motor responses, which are carried out by muscles, and secretory responses, which are carried out by glands.

Coordination Systems

• Nervous system: Receives and transmits information rapidly via electrical impulses through sensory neurons and processes them in the CNS. Responses are

Non-specific defenses

act against any type of microorganism or foreign particle. This action is carried out by phagocytes: white blood cells that trap and eliminate pathogenic microorganisms. This process is called phagocytosis.

INFLAMMATORY RESPONSE

is a non-specific defense mechanism. When pathogens get through the external barriers, the blood cells dilate to increase the blood flow. The result is pus.

Specific defenses

act against specific microorganisms or foreign molecules. Other types of leukocytes, called lymphocytes, produce proteins called antibodies. Antibodies are specific for each microorganism and destroy or inactivate the invading agents.

INCUBATION - this is the time between the moment the pathogenic agents invade organisms and the... Continue reading "Understanding Body Defenses and Diseases: A Comprehensive Guide" »

Classification of Living Organisms into Three Domains

Living organisms were originally divided into five kingdoms based on the presence of certain structural features. In 1978, this system was refined to account for clear biochemical differences between living organisms, specifically differences in rRNA sequences. According to the three-domain classification scheme, there are three distinct types of cellular organisms to which all living things belong:

• Eukarya: Contain a membrane-bound nucleus (includes plants, animals, protists, and fungi).
• Eubacteria: Lack a nucleus and consist of the traditional or 'true' bacteria (e.g., most pathogenic forms, E. coli, S. aureus, etc.).
• Archaea: Lack a nucleus and consist of the extremophiles or 'ancient' bacteria

Laboratory Exam Questions

Cell Functions and Observations

2) Write down the function of the parts that you see in the sample. Intense blue?

• Cell membrane: Separates the inside and outside of the cell, and controls what goes in and what goes out.
• Nucleus: Contains the genetic information and the nucleolus, where ribosomes are produced.
• Cytoplasm: A gel-like fluid where organelles are located.
• Mitochondria: Organelles that break down sugars and produce energy.

Yes.

3) Which part of the cell stains the most?
The cytoplasm.

4) Do you see any organelles? Why?
No, because they are so small.

5) What are the small blue dots in the samples?
Organelles.

Levels of Biological Organization

• Atom: Consists of the atoms of the chemical elements that make up living things.

Cell Organization and Structure

Cells in Humans (Eukaryotic Cells)

Cell Membrane

The outermost membrane, a lipid bilayer, controls what enters and exits the cell. This structure is also used in vaccine production to hold mRNA.

Mitochondria (Mitochondrion)

The powerhouse of the cell, responsible for ATP (Adenosine triphosphate) production. The ATP production rate depends on the folds of cristae. Some cells, like liver cells, have multiple mitochondria. The mitochondrion contains a matrix, a thick liquid with a high concentration of enzymes that facilitate ATP production.

Lysosome

The cell's recycle bin.

Golgi Apparatus

Packages proteins for transport in and out of cells.

Rough Endoplasmic Reticulum

Creates proteins.

Smooth Endoplasmic Reticulum

Creates... Continue reading "Cell Biology: Structure, Function, and Chemical Reactions" »

Human Eye Structure and Function

Key Components:

• Conjunctiva: Thin, transparent membrane lining the front of the sclera. It's moistened by tears, produced in the tear glands, which contain lysozyme, an enzyme that kills bacteria.
• Pupil: Opening in the iris through which light passes. It controls the amount of light entering the eye and appears black due to the black pigment of the choroid.
• Lens: Clear structure that allows light into the eye. It's made of stiff jelly and can change shape to focus light.
• Iris: Colored part of the eye that responds to light.
• Cornea: Transparent, protective layer at the front of the eye.
• Suspensory Ligaments: Fibers supporting the lens. When pulled tight, the lens is thin; when loosened, the lens is thicker.
• Ciliary Muscles:

Ecology

The scientific study of how organisms interact with each other and with their non-living environment.

Ecological Niche

The manner in which an organism uses the resources in, and is influenced by the conditions of its habitat.

Habitat

The physical place, or type of place, where an organism lives.

Physical Adaptation

Genetically-inherited characteristics that enable a given organism to survive and reproduce using a given niche.

Niche Partitioning

The division of niches between species so as to cut down on competition.

Resource

A material that is used, and potentially used up.

Environmental Conditions

Background features of the habitat.

Fundamental Niche

The largest array of resources an organism can utilize.

Realized Niche

The actual set of resources... Continue reading "Ecology: The Study of Organism Interactions and Adaptations" »

Epithelial Tissue Types

Simple Squamous Epithelium

Function: Reduces friction; controls vessel permeability; performs absorption and secretion.

Locations: Mesothelia lining pleural, pericardial, and peritoneal cavities; endothelia lining heart and blood vessels; portion of kidney tubules (thin sections of nephron loops); inner lining of cornea; alveoli of lungs.

Stratified Squamous Epithelium

Function: Provides physical protection against abrasion, pathogens, and chemical attack.

Locations: Surface of skin; lining of mouth, throat, tongue, esophagus, rectum, anus, vagina.

Simple Cuboidal Epithelium

Locations: Glands, ducts, portion of kidney tubules, thyroid gland.

Stratified Cuboidal Epithelium

Function: Protection, secretion, absorption.

Locations:... Continue reading "Epithelial and Connective Tissues: Functions and Locations" »

Nucleus:

Converts genetic material, controls all the cell, and contains nucleolus.

Mitochondria:

Converts solar energy in food to usable compounds.

Chloroplast:

Converts solar energy to chemical energy stored in food.

Cytoskeleton:

Maintains cell shape and helps cell move.

Ribosomes:

Synthesize proteins.

Endoplasmic Reticulum:

Assembles proteins and lipids.

Vacuoles and Vesicles:

Store materials.

Centrioles:

Organize cell division.

Cell Membrane:

Regulates materials that enter and leave the cells.

Golgi Apparatus:

Packages proteins and lipids for storage or transport out of the cell.

Cell Wall:

Shapes, supports, and protects cell.

Lysosomes:

Break down and recycle macromolecules.

Cytoplasm:

Gel-like mixture, surrounded by cell membrane, contains hereditary... Continue reading "Functions of Cell Organelles" »