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

Ecosystem Dynamics

An Ecosystem is a system formed by a group of organisms of different species or Biocenosis, the environment in which they live, and its physical and chemical characteristics or Biotope and the Interactions that are established between them.

Environmental factors are all the components of the ecosystem that have an Impact on the Biocenosis through their Presence or Variation.

Environmental factors determine:

• Distribution and Composition of the Biocenosis: the type and number of populations that make it up.
• How many organisms are present in each population.
• The Adaptations the organisms exhibit.

Types of Environmental Factors

Abiotic Factors

Are the Physical and Chemical components of an ecosystem, their variation, modifies the life... Continue reading "Ecosystem Dynamics: Biotic and Abiotic Factors" »

Essential Nutrients

Carbohydrates, proteins, and lipids are needed in significant amounts, while vitamins, minerals, and water are also crucial. Most foods are concentrated sources of one or two nutrients.

Food Groups

Foods are typically classified into five main groups:

• Grains
• Vegetables
• Fruits
• Milk
• Meat and Beans

Calories represent energy.

Carbohydrates

Carbohydrates provide us with ATP (energy).

• Two most important types: fructose (easy to absorb because it is a monosaccharide) and glucose (also a monosaccharide and the main carbohydrate in the blood).
• Other types: sucrose, maltose, and lactose. These are more difficult to absorb because they are disaccharides (two molecules linked).

Polysaccharides (Hard to Digest)

Polysaccharides are composed of many... Continue reading "Understanding Essential Nutrients" »

TROPHIC LEVEL = consists of all the organims in an ecosystem which obtain their food in the same way.

Cellular Transport and Water Potential

Diffusion

The movement of molecules from an area of high concentration to an area of low concentration through a partially permeable membrane. (Osmosis is the same but with water molecules)

Concentration Gradient

The difference in concentration of a substance between two different areas.

Active Transport

The uptake of particles by cells against a concentration gradient. It requires energy and a carrier protein.

Partially Permeable Membrane

A membrane that allows small molecules of water and certain solutes but does not allow the passage of large solute molecules.

Kinetic Energy

The energy of movement

Brownian Motion

The random movement of particles

Water Potential

The ability for a substance or cell to accept more water.... Continue reading "Understanding Key Concepts in Biology and Physics: Diffusion, Energy, and Heat Transfer" »

1. What kind of organelles do photosynthetic Protista contain?

• Multicellular and Unicellular

2. The main body of Fungi is called?

• Mycelium

3. Plants produce ________ for our survival

• Oxygen

4. What are the 2 transport plant tissues called?

• Xylem and Phloem

5. What is the smallest group of Bryophytes?

• Hornworts

6. A plant with a fibrous root system and leaves with parallel venation would also have?

• None of the above

7. Where does pollen transfer on plants to start reproduction?

• Stigma

8. If a farmer wanted a more loosely packed cluster of grapes, he would most likely spray the immature bunches with?

• Gibberellins

9. Who formulated for the first time the Theory of evolution?

• Lamarck

10. What is not inferred from Darwin's Theory?

• None of the above

11. What is the... Continue reading "Biology Quiz: Organisms and Their Characteristics" »

Infectious Diseases: An Overview

Changes to body physiology that disrupt normal body functions and are caused by microorganisms are called infectious diseases. This explanation, established by Louis Pasteur and Robert Koch, is called the germ theory of disease.

Causes of Infectious Diseases

Infectious diseases are caused by various microorganisms, including:

• Viruses
• Bacteria
• Fungi
• Protists
• Parasitic worms

Disease-causing microorganisms are also called pathogens. Koch also developed a series of rules, known as Koch's postulates, that help scientists identify which organism causes a specific disease.

While many microorganisms are symbionts that are either harmless or beneficial, pathogens cause disease by:

• Destroying cells
• Disrupting body functions
• Releasing

Common Knee Injuries

Knee Plica

Fetal knee development involves three chambers that typically merge into one. The internal walls (plica) separating these chambers may persist. While often asymptomatic, the medio-patellar plica is most prone to causing issues. Symptoms can mimic meniscus injury, leading to catching and locking sensations.

Patellar Subluxation and Dislocation

Occurs at the patellofemoral joint, with lateral dislocations being the most common.

Knee Joint Dislocation

Occurs at the tibiofemoral joint and often involves tears of the MCL, ACL, LCL, and joint capsule.

Patellar Tendon Rupture

A complete tear of the quadriceps or patellar tendon, typically at its attachment to the patella.

Medial and Lateral Collateral Ligament Injuries

• Medial

Characteristics of Poriferans

Poriferans, also called sponges, are aquatic organisms (the majority of them are marine organisms) that either have no symmetry or have radial symmetry. Their bodies, which have a tube shape, a cup shape, or an irregular shape, have multiple pores that are interlinked by thin channels. These channels lead to a central cavity, called the atrium, which is linked to the outside by an opening called the osculum. Inside the channels, there are cells known as choanocytes, which are specialized in capturing food.

Poriferans stay upright due to a skeleton made of small spines called spicules. They feed by filtration. Water, which contains food particles, enters through the pores and exits through the osculum with the food... Continue reading "Characteristics of Poriferans: Aquatic Organisms with Unique Structures and Reproduction" »

Microorganisms and Diseases

Microorganisms and associated diseases:

• Viruses: Common cold
• Bacteria: Pneumonia
• Protozoa: Malaria
• Fungi: Athlete's foot

Infectious Disease Transmission

Methods of infectious disease transmission:

• Waterborne: Cholera
• Vector-borne: Malaria
• Foodborne: Salmonella
• Airborne: Influenza (the flu)

Types of Diseases

Infectious Diseases: Influenza, AIDS, Gonorrhea, Tetanus, Measles, Tuberculosis

Non-Infectious Diseases: Diabetes, Lung cancer, Heart attack, Alzheimer's disease, Arthritis

Infections and Defenses

Infections and the body's defenses:

• Infected wound: Skin
• Intestinal infection: Large intestine
• Respiratory infection: Respiratory tract
• Vaginal infection: Bladder

Sexually Transmitted Diseases (STDs)

Three common sexually transmitted diseases:... Continue reading "Human Biology: Microorganisms, Diseases, and Reproduction" »

Human Body Organization

The human body is structured in a hierarchical manner, from the smallest components to the entire organism and its interactions within an ecosystem.

1. Subatomic Level

Consists of subatomic particles, i.e., protons, electrons, and neutrons (and sub-particles like quarks and leptons).

2. Atomic Level

Formed by atoms, the bioelements found in living beings. These include:

• Primary Bioelements: Essential for forming organic biomolecules (C, H, O, N, P, S), constituting 96% of dry living matter.
• Secondary Bioelements: Constitute 3% of dry living matter.
• Trace Elements: Present in small amounts but crucial for health (e.g., iron, iodine).

3. Molecular Level

Molecules are formed by grouping two or more atoms. Biomolecules in living beings... Continue reading "Human Body Organization: From Atoms to Ecosystems & Cell Basics" »