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

Bohr Shift

In the cytoplasm of red blood cells, the enzyme carbonic anhydrase catalyzes the following reaction: CO₂ + H₂O ⇌ H₂CO₃ (carbonic acid). The carbonic acid then dissociates: H₂CO₃ ⇌ H⁺ + HCO₃^-. Hemoglobin readily combines with the hydrogen ions, forming haemoglobinic acid (HHb), which releases the oxygen it is carrying.

The Cardiac Cycle

• 1. Atrial systole: Both atria contract. Pressure forces the atrioventricular valves open, and blood flows from the atria into the ventricles.
• 2. Ventricular systole: The ventricles contract. Atrioventricular valves are pulled shut as ventricular pressure exceeds atrial pressure. Semilunar valves are forced open, and blood rushes into the arteries.
• 3. Ventricular diastole: The heart muscle relaxes. Semilunar

The Sounds of Language

A Guide to Phonetic Symbols

Consonants

Sensory Receptors and Sensory Nerves

Sensory Receptors

Information from the environment and internal organs is detected by sensory receptors. These receptors can be:

• Surrounded by cells (not neurons)
• Connected with a neuron (sensory nerve) in which they will generate action potentials
• Specialized to respond to one particular form of energy

There are many different types of sensory receptors:

• Mechanoreceptors - detect touch and pressure
• Thermoreceptors - detect cold and warmth
• Nociceptors - detect pain
• Electromagnetic receptors - detect light
• Chemoreceptors - detect taste, smell, blood O₂ and CO₂ concentration, blood glucose, amino acids, and fatty acids

A receptor can be excited by:

• Mechanical deformation - stretches the receptor, opening ion channels
• Application

Sensory Cells and Structures

Rod Cells

Cone Cells

Hair Cells

Cochlea

The Nervous System: Divisions and Functions

Central Nervous System (CNS)

Peripheral Nervous System (PNS)

Somatic Nervous System

Autonomic Nervous System

External Anatomy of the Perch

• 1. Head: Structurally supportive and protective.
• 2. Eye: Visual stimuli.
• 3. Nares: Avenue for water to enter the oral cavity.
• 4. Mouth: Made up of the mandible and maxilla.
• 5. Operculum: Covers and protects soft gills.
• 6. Pectoral fin: Used like paddles; assist in direction change.
• 7. Anterior dorsal fin: Serves as a rudder for stability.
• 8. Posterior dorsal fin: Supported by rays; serves as a rudder for stability.
• 9. Caudal fin: Propels the fish through the water.
• 10. Pelvic fin: Assists in stability when swimming.
• 11. Anal fin: Assists in stability when swimming.
• 12. Lateral line: Sensory organ that allows the perch to detect changes in pressure, movement, and vibration.

Internal Skeletal and Sensory Structures

• 13. Gills:

How Organisms Obtain Nutrients

Unicellular Organisms: Direct Nutrient Exchange

Unicellular living organisms perform nutrition by exchanging substances directly with their surrounding environment. Nutrients and oxygen enter the cell through a plasma membrane, through which waste is also expelled.

Multicellular Organisms: Systemic Nutrition

Multicellular living organisms, such as human beings, have most cells that do not come into direct contact with the outside world and cannot exchange substances with it directly. The nutrition function is performed through the joint action of different systems that act as intermediaries between the outside world and cells.

Essential Body Systems for Human Nutrition

The Digestive System: Nutrient Absorption

The digestive

Fundamental Ecological and Biological Concepts

Biodiversity: The Variety of Life

Biodiversity refers to the varying or different life forms found on Earth. It encompasses several types:

• Genetic Diversity: The variety of genetic materials within a species or a population.
• Species Diversity: The number and abundance of species present in different communities.
• Functional Diversity: The biological and chemical processes, such as energy flow and matter recycling, needed for the survival of species, communities, and ecosystems.
• Ecological Diversity: The variety of terrestrial and aquatic ecosystems found in an area or on the Earth.

Evolution: Changes in Organism Genetic Makeup

Evolution refers to the changes in a population of organisms' genetic makeup... Continue reading "Essential Concepts in Ecology and Environmental Science" »

Human Nutrition and Body Systems

The digestive, respiratory, excretory, and circulatory systems all play a role in nutrition.

• Digestive system: Introduces foods into the body, and prepares and transforms it to enable its use by cells.
• Respiratory system: Obtains the oxygen cells need and eliminates carbon dioxide produced during cell metabolism.
• Circulatory system: Transports nutrients and oxygen to cells and releases waste substances.
• Excretory system: Releases waste substances outside the organism.

The Digestive System: Function and Structure

The digestive system breaks nutrients into parts small enough for your body to absorb and use for energy, growth, and cell repair. It is made up of the gastrointestinal (GI) tract and the accessory glands:... Continue reading "Human Digestive System: Organs, Functions, and Processes" »