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

Antigen-antibody reactions

Ag + Ab AgAb

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·reversible reaction as there are formed noncovalently biochemical bonds

·strength of such interactions is called affinity

·different immunoglobulins within an individual show a wide range of affinity

·valence - number of epitope-binding sites of one immunoglobulin molecule

·avidity - describes the collective affinity of multiple binding sites (affinity + valence)

·e.g. although IgM has a low affinity, its avidity is quite high due to 10 epitope-binding sites

·...

Primary and secondary immune response

·primary immune response

ofirst contact to a foreign antigen that has to be eliminated from the body

ofirst a lag/induction phase (ca. 7-9 days or even up to months) occurs in which no antibody is produced,... Continue reading "Antibody Reactions, Immune Response, and Immunologic Memory" »

Core Concepts in Biology

Biodiversity

Species that inhabit or have ever inhabited the Earth.

Adaptation

The accumulation of changes in a living being to suit the environment in which it lives.

Types of Adaptation

• Structural: Affects organs and allows for specific functions, e.g., birds' beaks.
• Physiological: Affects the organism's function and metabolism.
• Behavioral: Actions that provide advantages, e.g., migration.

Evolutionary Theories

Biodiversity and Evolution

Slow changes in living beings over millions of years.

Fixism (Georges Cuvier)

Organisms were created through divine creation and became extinct due to catastrophes. This theory posited that species could not change, a view contrasted by later evolutionary theories.

Lamarckism (Jean-Baptiste de

The Digestive System

The digestive system is responsible for the ingestion, digestion, absorption, and elimination of food. It transforms food into nutrients through three main processes:

1. Mechanical Digestion: Chewing, grinding, crushing, and mixing of food to break it down into smaller pieces.
2. Chemical Digestion: Digestive juices break down macromolecules in food into smaller molecules that can be absorbed.
3. Absorption: Nutrients are absorbed into the bloodstream and transported to cells throughout the body.

Ingestion

Ingestion begins when food enters the mouth. Key steps include:

• Mastication (Chewing): Teeth tear and break food into smaller pieces.
• Salivation: Saliva mixes with food, forming a bolus and aiding in swallowing.
• Swallowing: The tongue

NICOTINE: *afects the brain, it is a simulant, which means that it make you feel more active and alert. *makes heart rate and blood presure increase, which leads to heart desease. *it is an addictive, it is very hard to do without it.

Inorganic biomolecules

Essential for non-living things.

• Water: The most abundant substance found in living things. It makes up about 65% of the human body.
• Mineral salts: Substances that can be found in living things in the form of dissolved ions, such as sodium ion.

Organic biomolecules

Unique to living things. Structures made up of carbon.

• Carbohydrates: Made of carbon and water.
• Lipids: Fats, phospholipids, and cholesterol.
• Proteins: Chains of amino acids.
• Nucleic acids: Groups of nucleotides.

The cell: Functions

• Structural
• Functional
• Basic
• Biological

Prokaryotic cell

• No nucleus
• Organelles: Ribosomes
• Bacteria are prokaryotes
• Membranes: Cell membrane, cell wall, and bacterial capsule (not always)
• Flagella and Fimbriae

Eukaryotic cell

• Nucleus
• Cell membrane: two

Cell Organelles

Mitochondria: Oval-shaped organelles with two membranes. Through cellular respiration, mitochondria produce energy for the cell.

Vesicles: Small, rounded organelles that store, transport, or digest cellular substances. Lysosomes are rounded vesicles produced by the Golgi body.

Endoplasmic Reticulum: A network of interconnected membranous sacs and channels. There are two types:

• Rough ER: Connected with the nuclear envelope and ribosomes.
• Smooth ER: This type has no attached ribosomes.

Golgi Body: Flat, membranous sacs arranged in layers. Secretory vesicles transport substances out of the cell.

Centrosome: Consists of two centrioles: perpendicular cylindrical structures composed of microtubules. They are surrounded by other microtubules... Continue reading "Cell Organelles and Food Preservation Techniques" »

Metre: mm = 10^-3, hm = 10^-6, nm = 10^-9

Plasma Membrane

The plasma membrane is partially permeable and contains the exchange of materials.

Chromatin

Chromatin is a mass of chromosomes during nuclear division, which is the material of which chromosomes are made.

Nucleolus

The nucleolus is a small structure, one or more inside the nucleus. Its function is to manufacture ribosomes.

Protoplasm

Protoplasm refers to all the living material inside the cell.

Cytoplasm

Cytoplasm refers to the contents of a cell excluding the nucleus.

Mitochondrion

The mitochondrion is the organelle in eukaryotes where aerobic respiration takes place.

Cell Wall

The cell wall gives the cell a definite shape and prevents the cell from bursting when water enters by osmosis.

Vacuoles

Vacuoles... Continue reading "Cell Structures and Functions" »

All cells in your body are surrounded by a liquid environment. They depend on it to stay alive. The internal environment is made up of the interstitial fluid and the circulating fluids. Lymph is the fluid that flows through the lymphatic vessels. It is formed from the remaining interstitial fluid. Blood is the fluid in charge of transporting substances through the inside of blood vessels. Interstitial fluid is the fluid that surrounds every cell. Cells extract nutrients, oxygen and release into the waste and carbon dioxide produced in cell metabolism. The circulatory system connects the system involved in the nutrition function with the interstitial fluid that surrounds the cells in the body. It has 2 systems: the cardiovascular system through... Continue reading "Understanding the Circulatory System and Its Functions" »

Organization of Life

Atoms: smallest unit of an element that still retains the element's properties.

Molecules: two or more joined atoms of the same or different elements.

Cell: smallest unit of life that can live and reproduce on its own or as part of a multicellular organism.

Multicellular organisms: made of specialized, interdependent cells that are often organized into:

• Tissues
• Organs
• Organ systems

Population: consists of individuals of the same species in a specified area.

Community: consists of all populations occupying the same area.

Ecosystem: a community interacting with its physical and chemical environment.

Biosphere: includes all regions of Earth's atmosphere, waters, and land where we find living organisms.

DNA is inherited.

Inheritance: an... Continue reading "Organization of Life and Enzymes: An Overview" »

The Digestive System

Liver

The liver, the largest internal organ, contains ducts called hepatocytes. These hepatocytes collect bile secreted by liver cells. The liver plays a crucial role in the metabolism of carbohydrates, lipids, and proteins.

Gallbladder

The gallbladder is a pear-shaped structure located under the liver. Its primary function is to store bile.

Pancreas

The pancreas is a long, narrow gland with two ducts, located on the left side of the abdomen.

Small Intestine

The small intestine starts at the pylorus and ends at the ileocaecal valve, where it joins the large intestine. It has two main parts:

• Duodenum: Secretes bile and pancreatic juice into this section.
• Jejunum and Ileum: Form the rest of the intestine. The small intestine is covered