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

Phospholipid molecules form a bilayer - phospholipids are fluid and move laterally

Peripheral proteins are bound to either the inner or outer surface of the membrane

Integral proteins - permeate the surface of the membrane

The membrane is a fluid mosaic of phospholipids and proteins

Proteins can move laterally along membrane

Diffusion is the movement of particles from a region of high concentration to a region of low concentration, and is the result of the random motion of particles.

Facilitated diffusion is similar to simple diffusion, except that it requires channel proteins or carrier proteins, which are specific to the molecules being transported across the plasma membrane from high concentration to low concentration.

Osmosis is the passive movement... Continue reading "Cell Membrane Structure and Function" »

Fibra:Fiber is a complex carbohydrate of plant origin. Humans
cannot digest fiber or use it as a source of energy or
matter, but it is nonetheless essential for the functioning
of the digestive system.

Nutrients:Organic nutrients: are complex molecules produced by

Inorganic nutrients: are simple molecules that can be
found in living organisms, but have not been produced by
them. These nutrients are essential to your body but do
not supply any energy.
○ Minerals (such as calcium and sodium)
○ Water
○ Oxygen

Vitamins:Vitamins are organic components that the body either
cannot produce or produces only in insufficient
quantities.
● These must be obtained from food.
● All vitamins are needed in small quantities and they are
essential for regulating many... Continue reading "Where is cellobiose found in living organisms" »

Homeostasis and Environmental Response

All living things interact with their environment, including their surroundings and other organisms.

The environment is constantly changing. To survive and reproduce, living organisms must detect these changes and respond appropriately.

Responding to Stimuli

1. A stimulus is detected by receptors (structures or organs).
2. The stimulus is relayed to coordination systems, which interpret the signal and produce a response.
3. The organism responds using effectors (organs or structures).

Maintaining Internal Balance

To survive, living organisms must regulate their internal conditions.

Examples of internal conditions include temperature, water content, and concentrations of mineral salts and glucose in the blood.

Changes in... Continue reading "Homeostasis and Stimuli in Living Organisms" »

Blood: Composition and Vital Functions

Blood Composition

• Blood Plasma: The liquid component of blood.
• Blood Cells:
  • Red Blood Cells (Erythrocytes): Primarily responsible for oxygen transport.
  • White Blood Cells (Leukocytes): Key components of the body's immune and defense system.
  • Platelets: Essential for blood clotting and preventing excessive bleeding.

Key Functions of Blood

Blood serves as an effective transport system for various substances throughout the body:

• Oxygen Transport: Carries oxygen gas, primarily bound to hemoglobin. When hemoglobin is highly saturated with oxygen, it is called oxyhemoglobin.
• Nutrient and Waste Transport: Moves nutrients to cells and carries metabolic waste products away for excretion.
• Heat Distribution: Helps regulate and

Heart Anatomy and Function

Chambers and Valves

The heart is a muscular, hollow organ divided into four chambers:

• Upper Chambers (Atria): Left atrium and right atrium.
• Lower Chambers (Ventricles): Left ventricle and right ventricle.

Between the atrium and ventricle, the atrioventricular valve allows blood flow from the atrium to the ventricle but prevents backflow. The valve between the left atrium and ventricle is bicuspid, while the valve between the right atrium and ventricle is tricuspid.

Blood Circulation

Cardiac Cycle

• Atrial Systole: Atria contract, pumping blood into the ventricles through open atrioventricular valves.
• Ventricular Systole: Ventricles contract, sigmoid valves open, and blood flows into the pulmonary artery and aorta. Atrioventricular

NO BANK/FIB-MULTI Panceras

Endocrine Functions § Pancreatic islets § Secrete hormones insulin and glucagon into blood Exocrine functions § Secretes pancreatic juice into duodenum § Alkaline fluid introduced with enzymes neutralizes chyme from stomach Pancreatic Juice

• Water, bicarbonate solution, enzymes
• Bicarbonate solution: neutralizes gastric HCL & shift pH of duodenum to 8
• Enzymes: § Pancreatic amylase: digests salts § Trypsinogen - digests proteins § Lipase - digests triglycerides

Agriculture:

Deliberate land modification through plant cultivation and raising animals for food or profit Dominant economic activity Requires physical and demographic contributions in regions

Hemoglobin:

Globin combined with 4 iron atoms • 280 million molecules... Continue reading "Endocrine Functions of the Pancreas and Other Organ Systems" »

Menstrual Cycle

Pre-menstrual phase: the lining of the uterus begins to break down, progesterone decreases. Menstruation: the endometrium is detached, loss of blood and it is caused by progesterone. Usually it lasts 4 days. Repair phase: the lining of the uterus starts to thicken and becomes more stable. Increase in the concentration of estrogen. Ovulation: occurs around day 14, the ovum is released, there is a peak of estrogen and they are the most fertilized days. Receptive phase: the lining of the uterus is well developed if the ovum has been fertilized it implants itself in the tissue. Hormones: FSH: stimulates the follicle (brain) LH: produces ovulation (brain). Estrogen: creates new endometrium (ovary). Progesterone: makes the endometrium... Continue reading "Understanding the Menstrual Cycle, Pregnancy, and Reproduction" »

Chapter 7 (Sections 1, 2, and 3)

Nutrition: The Science or Study of Food and the Ways in Which the Body Uses Food

Nutrients: Substances in Food that Provide Energy or Help Form Body Tissues and Are Necessary for Life and Growth

Carbohydrates: Class of Energy-Giving Nutrients that Includes Sugar, Starches, Fiber, and Glycogen

Fats: Class of Energy-Giving Nutrients and Are the Main Form in Which Energy Is Stored in the Body

Proteins: Class of Energy-Giving Nutrients Made Up of Amino Acids Which Are Needed to Build and Repair Body Structures and to Regulate Processes in the Body

Glycogen: Made in the Body Which Is Made of Many Glucose Units Linked Together Stored in the Muscle and Liver of Human and Animals Can Be Broken Down to Provide a Quick Source

• In the case of partial injuries, some sensation and movement may be retained below the level of the injury.

• In complete injuries, there is a loss of sensation and total muscular paralysis below the level of the injury

• Depression is a mental illness that often takes the form of low mood and an inability to lead a normal life

Essential Nutrients: A Comprehensive Guide

1. Six Classes of Nutrients

• Carbohydrates (provide energy)
• Fats (provide energy)
• Proteins (provide energy)
• Vitamins (do not provide energy)
• Minerals (do not provide energy)
• Water (does not provide energy)

2. Functions of Carbohydrates, Proteins, and Fats

Carbohydrates

Carbohydrates are broken down into glucose, which is the body's main source of energy. They are important for the brain, nervous system, kidneys, and muscles. Carbohydrates are stored in the liver and muscles for later use as energy. Fiber, a type of carbohydrate, promotes bowel health by allowing waste to move more quickly through the gut. Carbohydrates are found in grains, fruits, milk, nuts, seeds, beans, and vegetables.

Proteins

Proteins build... Continue reading "Essential Nutrients: A Comprehensive Guide to Macronutrients, Micronutrients, and Their Functions" »