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

Blood: Functions and Composition

Blood is a type of connective tissue. It is a thick red liquid made up of specialized cells suspended in a watery solution of molecules and ions. Blood transports nutrients and oxygen to the cells and carries waste residues to where they can be eliminated. Besides that, it regulates body temperature, pH and water volume, transports hormones, and defends our body from infections or from excessive blood loss when we get wounded. Blood is the only liquid tissue in our body because the matrix in which blood cells are immersed is liquid. The liquid component of blood is called plasma and it represents about 55% of blood volume.

Plasma: Composition and Role

Plasma is a pale yellow liquid. About 90% of it is water. The... Continue reading "Human Blood: Composition, Functions, Cardiac Cycle & Edema" »

Auto or Self Antigens

Antigens present in one's own cells.

Altered by the action of bacteria, viruses, chemicals, or drugs as a non-self.

Auto antibody

Altered cell (Auto Ag) - elicits the production of Antibody.

Autoimmunity (misnomer, alternative = auto allergy)

Immune response of auto Ab against self Ag.

Humoral or cell-mediated immune response against the constituents of the body's own tissues.

There are more than 80 different kinds of diseases caused by autoimmunity.

Causes of Autoimmune Diseases

Sequestered or Hidden antigens

Ag in the secluded places - are not accessible to the immune system.

Neo antigens

Altered or Modified Antigens – by physical (irradiation), chemical (drugs), or microbial agents (intracellular viruses).

Cessation of Tolerance

It... Continue reading "Auto or Self Antigens: Causes and Effects of Autoimmunity" »

Behind the iris is a lens which changes shape in order to focus the image.

Photosynthesis and Cellular Respiration

Photosynthesis

Photosynthesis is the process by which plants convert carbon dioxide and water into glucose and oxygen, using light energy. This endothermic reaction can be summarized by the following equation:

6CO₂ + 6H₂O -> C₆H₁₂O₆ + 6O₂

The rate of photosynthesis is influenced by several factors, often referred to as limiting factors. These include:

• Light intensity: Increased light levels generally lead to a higher rate of photosynthesis until an optimum level is reached.
• Carbon dioxide concentration: Higher levels of carbon dioxide can enhance the rate of photosynthesis, up to a certain point.
• Temperature: Plants in their ideal temperature range perform photosynthesis more efficiently than those outside

Common Health Disorders

Sensory Organ Issues

• Eyes:
  • Short-sightedness (Myopia): Eyeball too long. Images focus in front of the retina.
  • Long-sightedness: Images focus behind the retina.
  • Cataracts: The crystalline lens loses transparency until it becomes opaque.
  • Conjunctivitis: Inflammation in the conjunctiva.
  • Astigmatism: Irregularly shaped cornea; objects appear distorted or blurred.
• Skin:
  • Psoriasis: Skin patches covered with silver scales.
  • Urticaria: Allergic reaction, often to food or medicine.
• Ear:
  • Otitis: Acute inflammation.
  • Deafness: Hearing loss.
• Nasal Cavity:
  • Rhinitis: Inflammation in the nasal respiratory membrane, often caused by allergies.

Mental Health Conditions

• Phobias: An anxiety disorder due to a persistent, irrational fear (e.g., fear of confined

Microbial Secretion Systems

Matching

Which secretion system:

• Moves protein from the periplasmic space to the exterior? 2, 4, 5
• Moves DNA from one cell to another through conjugation? 4
• Moves protein from cytoplasm to exterior (not into another cell)? 1, 3
• Relies on Sec to do the first step of transportation? 2, 4, 5
• Requires ATP? All
• A domain of the protein itself forms a beta-barrel that inserts into the outer membrane (i.e., forming a pore), allowing the rest of the protein to pass through? 5
• The protein being transported carries a C-terminal signal peptide? 1
• The preprotein (before final folding) being transported carries an N-terminal signal peptide? Sec

Viral Multiplication

Six Steps to Viral Multiplication:

1. Attachment to host cell
2. Entry
3. Uncoating of

Plant Nutrition Fundamentals

Photosynthesis Definition

Photosynthesis is the process by which plants manufacture carbohydrates from raw materials using energy from light.

Photosynthesis Word Equation

The word equation for photosynthesis is: carbon dioxide + water → (in the presence of light and chlorophyll) → glucose + oxygen.

Photosynthesis Balanced Equation

The balanced chemical equation for photosynthesis states that the combination of carbon dioxide, water, and light energy produces a carbohydrate (glucose) and oxygen.

The chemical formula is: 6CO₂ + 6H₂O + Light Energy → C₆H₁₂O₆ + 6O₂.

Chlorophyll's Role in Energy Transfer

Chlorophyll transfers light energy into chemical energy stored in molecules, enabling the synthesis of... Continue reading "Plant Nutrition and Photosynthesis Essentials" »

Cellular Respiration

1. Definition and Chemical Equation

Cellular respiration is the chemical reaction in which glucose and oxygen are converted into water, carbon dioxide, and energy (ATP). The balanced chemical equation for cellular respiration is: C₆H₁₂O₆ + 6 O₂ --> 6 CO₂ + 6 H₂O + ATP

2. Location of Respiration

Cellular respiration takes place in the mitochondria of living cells.

3. Phases of Respiration and ATP Production

Cellular respiration occurs in three stages: glycolysis, the Krebs cycle, and electron transport. Glycolysis takes place in the cytoplasm and results in a net gain of two ATP molecules.

4. ATP and Energy Production

ATP provides energy to the cell when it is broken down into ADP (adenosine diphosphate) and inorganic phosphate,... Continue reading "Cellular Respiration and Cell Cycle: Key Concepts and Processes" »

1. Central Nervous System

• Brain: Protected by the cranium and divided into:
  • Cerebrum: Interprets information from sense organs, controls language, memory, and thought. It produces voluntary responses.
  • Cerebellum: Controls basic movements and helps maintain balance.
  • Brain Stem: Controls involuntary movements.
• Spinal Cord: Protected by the vertebral column. It sends signals to and from the brain and facilitates involuntary responses or reflexes.

2. Autonomic Nervous System

• Sympathetic: Stimulates organs in case of emergency.
• Parasympathetic: Maintains the functioning of the body.

3. Neurons

Neurons are specialized cells of the nervous system that transmit nerve impulses.

4. Synaptic Transmission

The nerve impulse is transmitted from one neuron to another... Continue reading "Human Nervous and Endocrine Systems: Functions and Processes" »