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

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" »

Organs Involved in Excretion

Excretion is the process by which the waste products from cell metabolism are eliminated from the blood.

Kidneys

Kidneys eliminate toxic substances resulting from cell metabolism through the urine.

Lungs

Lungs expel carbon dioxide from cellular respiration.

Liver

Liver produces a liquid called bile that helps to eliminate waste from digestion through feces.

Sweat Glands

Sweat glands, exocrine glands of the skin, are responsible for sweat excretion. Sweat is a liquid that is very similar to urine, but more diluted.

Nephrons and the Formation of Urine

Nephrons are the basic functional units of the kidneys. Each kidney has about one million. Urine is a liquid made of water, salts, and waste. This is done using filtration and... Continue reading "Organs Involved in Excretion and the Formation of Urine" »

Explain the process of transcription in prokaryotes, including the role of the promoter region, RNA polymerase, nucleoside triphosphates and the terminator

A gene is a sequence of DNA which is transcribed into RNA and contain three main parts:

Promoter:  Responsible for the initiation of transcription

Coding Sequence:  The sequence of DNA that is actually transcribed

Terminator:  Sequence that serves to terminate transcription

State that eukaryotic RNA needs the removal of introns to form mature mRNA

Each exon is used to make a certain amino acid and the introns, must be removed so that they can code for the amino acids to form a protein.

Explain that each tRNA molecule is recognized by a tRNA-activating enzyme that binds a specific amino acid

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" »

Which Nerve Slows the Heart Down?

The Vagus Nerve

Function of Heart Valves

Heart valves ensure one-way blood flow.

Atrioventricular Valves

• Tricuspid valve (3 cusps): Located between the right atrium and right ventricle.
• Bicuspid (mitral) valve (2 cusps): Located between the left atrium and left ventricle.
• Chordae Tendineae: Also known as 'heart strings'.

Semilunar Valves

• Pulmonary semilunar valve: Directs blood from the right ventricle to the pulmonary trunk.
• Aortic semilunar valve: Directs blood from the left ventricle to the aorta.

Arteries vs. Veins

Arteries carry oxygenated blood away from the heart to the body, while veins carry oxygen-poor blood back from the body to the heart.

Three Functions of Blood

Blood has three main functions:

1. Transportation:

1. Human Beings and Health

The World Health Organization (WHO) defines health as 'the complete physical, mental and social well-being, not only the absence of disease'.

The Environment

Healthy surroundings should be free of biological, physical or chemical elements that are harmful to your health.

Personal Characteristics

Genetic factors, age and gender predispose people to suffer from certain types of illnesses.

Lifestyle

Healthy habits and lifestyles are very important for staying healthy.

Healthcare

It is essential to have an efficient healthcare system to guarantee public health.

Vital Signs

Vital signs are physiological parameters that inform us of our state of health or the evolution.

Cause -> Organic Alteration -> Symptoms and Signs ->

Continental Drift

Pangaea

Plankton

Holoplankton

Zooplankton

Meroplankton

Shark Anatomy and Physiology

Spiracles

Swim Bladder

Lateral Line

Cartilage

Operculum

Marine Reptiles

Crocodile Mothering

Marine Reptile Features