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

Key Plant Cell Terms: A Comprehensive Glossary

Amyloplast

Amyloplasts are non-pigmented organelles found in some plant cells. They are responsible for the synthesis and storage of starch granules through the polymerization of glucose. Amyloplasts also convert this starch back into sugar when the plant needs energy.

Cell Wall

The cell wall is a tough, usually flexible but sometimes fairly rigid layer that surrounds certain types of cells. It is located outside the cell membrane and provides these cells with structural support and protection, in addition to acting as a filtering mechanism. A major function of the cell wall is to act as a pressure vessel, preventing over-expansion when water enters the cell.

Nucleus

The nucleus is a membrane-enclosed... Continue reading "Key Plant Cell Terms: A Comprehensive Glossary" »

Amylase begins the digestive process by breaking down starch when you chew your food, converting it into a smaller carbohydrate. Pepsin helps digest the proteins in food because amylase is at the mouth and the pepsin at the stomach.

Chyle

Is a body fluid in the small intestine. It is turbid and milky due to the presence of emulsified fats. Is formed from the chyme during the digestion of fatty foods.

Intestinal Flora

Is the symbiotic bacteria occurring naturally in the gut.

Defecation

Is the final action of digestion, by which organisms eliminate solid, semisolid, or liquid waste material from the digestive tract via the anus.

Mechanical Digestion

This is the enzymatic breakdown of large, complex molecules found in food into smaller, simpler, more... Continue reading "Understanding Digestion, Blood Composition, and the Endocrine System" »

What is a Plasma Membrane, and Do All Cells Have One?

The plasma membrane encloses the cytoplasm and the cell's genetic material. It regulates what enters and exits the cell. Yes, all cells have a plasma membrane.

What Are the Two Central Tenets of Cell Theory?

• All organisms are composed of cells.
• Cells come only from preexisting cells.

What Are the Two Main Types of Cells?

• Prokaryotic cells lack a membrane-bound nucleus.
• Eukaryotic cells have a nucleus that houses DNA.

Where Do Prokaryotic Cells Store Their Genetic Material?

In the nucleoid.

What Domains Do Prokaryotic Cells Belong To?

Archaea and Bacteria.

What Are Three Characteristics of Prokaryotic Cells?

• They are much smaller and simpler than eukaryotic cells.
• They reproduce very quickly and effectively

Passive Transport Mechanisms

Diffusion: Movement Down the Concentration Gradient

Diffusion is the passive movement of particles from a region of high concentration to a region of low concentration, aiming to equalize solute concentration. Diffusion occurs naturally because more particles move from the region of higher concentration toward the region of lower concentration.

Simple Diffusion

Simple diffusion enables substances to passively cross cell membranes from a region of higher concentration to a region of lower concentration without using metabolic energy (ATP). Once the concentration of the substance is equal on both sides of the cell membrane, a state of equilibrium is reached.

Facilitated Diffusion

Large, charged, hydrophilic, and polar substances... Continue reading "Cell Transport Mechanisms: Passive vs. Active Movement" »

Essential Medical Concepts

Key Definitions in Health and Immunity

What is Health?

Health is a combination of physical, mental, and social well-being, indicating a state where an individual is not suffering from a disease.

Understanding Antigens

An antigen is a substance that is perceived by lymphocytes and triggers a specific immune response.

Phagocytes: Immune System Defenders

A phagocyte is a specific type of white blood cell that activates when a pathogen crosses the first line of defense.

The Body's Defense Mechanisms

Understanding Immunity and Protection

Non-Specific Immune Response

When a pathogen crosses the first line of defense, the second line of defense is activated. This non-specific response is carried out by specific white blood cells, such... Continue reading "Human Body Defenses and Therapeutic Interventions" »

Characteristics of Living Organisms

Movement

A change of position or place.

Respiration

A chemical process in which oxygen is used to release energy from sugar molecules. Most of it happens in the mitochondrion.

Sensitivity

The ability to detect or sense changes in the environment (stimuli) and to make responses.

Growth

A permanent increase in size by increasing cell number, cell size, or both.

Reproduction

The process that makes more of the same kind of organism.

Excretion

The removal of toxic materials, waste products, and excess substances from an organism.

Nutrition

The process in which nutrients are taken into the body and converted into simpler substances used for energy, growth, and tissue repair.

Cell Structure and Organization

Cells can be classified... Continue reading "Fundamental Concepts of Biology: Cells & Life Processes" »

1. Body Fluids

Our body is composed of approximately 60% water, distributed as follows:

• Intracellular fluids: 40%
• Extracellular fluids: 20%

Interstitial Fluid

All cells in our body are surrounded by fluid to obtain nutrients and expel waste. Interstitial fluids are essential for this process.

2. The Circulatory System

The circulatory system is responsible for transporting nutrients and waste, regulating temperature, and maintaining homeostasis. It consists of:

• Liquid: Blood
• Conduits: Arteries, veins, and capillaries
• Pump: The heart

2.a Blood

Blood is the liquid component of the circulatory system, composed of water, cells, and dissolved substances.

• Blood Plasma: Composed of 92% water, plus nutrients, gases, and waste.

2.b Capillaries

These are tiny vessels... Continue reading "Human Body Systems: Circulation, Excretion, and Homeostasis" »

Characteristics of Living Things

MRS GREN is an acronym used to remember the seven life processes: Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion, and Nutrition.

• Movement: Observed in living things through actions like jumping or processes like photosynthesis.
• Respiration: A chemical reaction in cells that breaks down nutrient molecules and releases energy for metabolism (e.g., plants release oxygen that is absorbed by other living things).
• Sensitivity: The ability to respond to stimuli, such as touch or light.
• Growth: The process of increasing in size, such as plants getting bigger.
• Reproduction: Male and female members of the same species producing offspring, which can be asexual (e.g., breaking in half) or sexual.
• Excretion:

Nutritional Requirements and Metabolism

Nutrition Defined

Nutrition: Food intake in relation to the dietary needs of the organism.

Autotrophic Nutrition

Autotrophic: The body's ability to synthesize essential substances for metabolism from inorganic substances. Autotrophs have no need for nourishment from other living beings.

Heterotrophic Processes and Transport

Heterotrophic: Done through movements of molecules and ions via the diffusion process. The cell controls its internal chemical composition to regulate the traffic of substances across the membrane. This occurs through two mechanisms:

• Active Transport: Moves against concentration gradients.
• Passive Transport: Moves toward concentration gradients.

Cell Reproduction and Division Cycles

Cell Reproduction

Pharmacology 2

Dependence: physical response, addiction: behavioral.

Pharmacodynamic principle Placebo effect: patient experiencing relief of symptoms or effect that cannot be attributed to medication. Receptor theory; receptor site, binding site for drug molecule, lock & key. Responses agonist(enhances support encourages response) antagonist( inhibits response drug fits receptor but fails to initiate) neutral(no response). Dose response relationship: inc drug concentration =inc potential receptor site=inc biological effect. Steady state: maintaining blood levels within therapeutic range.

Anti-inflammatories: Steroids: end in -one. NSAIDS: selective(COX2 inhibit celebrex) non selective: upset stomach (salicylates, propionic acid, enolic acid,... Continue reading "Pharmacology 2: Pharmacodynamics, Anti-inflammatories, and Homeostasis" »