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

Understanding Key Biological Systems and Health Concepts

Intestines

The intestines are a long, continuous tube running from the stomach to the anus. Most absorption of nutrients and water happens in the intestines. The intestines include the small intestine, large intestine, and rectum.

Excretory System

The excretory system is a passive biological system that removes excess, unnecessary materials from the body fluids of an organism.

Liver

The liver's main job is to filter the blood coming from the digestive tract before passing it to the rest of the body. The liver also detoxifies chemicals and metabolizes drugs.

Double Circulation

Double circulation describes the process where blood is first pumped into the lungs, where it becomes oxygenated, and... Continue reading "Key Biological Systems and Health Concepts Explained" »

Digestive System Diseases

Oral Cavity

• Tooth Decay

  Tooth enamel is destroyed by acids produced by bacteria that break down food fragments stuck between teeth. Tooth decay causes cavities to form, and bacteria in the cavities can then destroy the teeth.

• Gingivitis

  Inflammation of the gums caused by vitamin deficiencies or poor dental hygiene.

Stomach

• Gastroenteritis

  An infection affecting the stomach or intestine, caused by bacterial toxins. Symptoms include diarrhea, vomiting, abdominal pain, and fever.

• Gastritis

  Irritation of the gastric mucosa causing pain, acidity, and a burning sensation. Often caused by smoking, drinking alcohol, eating spicy foods, or taking medicine.

• Stomach Ulcer

  Damage to the gastric mucosa which causes the stomach cavity to come

Unit 3: Lessons 1

Bioelements

Atoms are linked together to form elements. A chemical element is formed by similar atoms.

Biomolecules

Atoms are linked together to make molecules. There are two types of molecules: inorganic and organic.

Cell

This is the smallest unit of living matter that can exist freely in a medium, as it can carry out all the functions of living beings.

Multicellular Levels

• Tissue: A group of cells similar in structure that work together to perform a specific function.
• Organ: Several tissues grouped together to make a structure with a specific function.
• Organ System: A group of organs with closely related functions.
• Organism: The complete unit of the living being.

Unit 3: Lesson 2

Enzymes

Most chemical reactions in living beings would... Continue reading "Essential Building Blocks of Life: From Atoms to Organisms" »

The Pulmonary Circuit

The pulmonary circuit begins in the right ventricle where deoxygenated blood is pumped through the pulmonary artery to each lung. The artery branches, finally becoming a network of capillaries that carry deoxygenated blood to the alveoli where gas exchange occurs. After gas exchange, oxygenated blood travels through the venous capillaries, the venules, and finally the pulmonary veins to the left atrium.

The Systemic Circuit

The systemic circuit begins in the left ventricle. Oxygenated blood is pumped through the aorta to the upper and lower body. It travels through the arteries, arterioles, and finally arterial capillaries to reach the cells. There, during cellular metabolism, nutrients and oxygen are collected while carbon... Continue reading "The Pulmonary and Systemic Circuits: Functions and Diseases" »

Anatomical Changes in Human Evolution

Anatomy is the scientific study of the structures of living things, including their systems, organs, and tissues.

Bipedalism: The Upright Stance

Bipedalism first appears with Australopithecus. Due to a climate change, the jungle turned into grassland, necessitating walking upright to see over the grass. This process required many transformations:

• The legs became longer.
• The arms became shorter.
• The hands were freed.
• The pelvis became narrower.

Encephalization: Brain Enlargement

Encephalization is the progressive enlargement and increasing complexity of the hominid brain. This change is due to the expansion of the cranial cavity.

Changes in Hand Structure

The palm became shorter and the fingers became longer. Hominids... Continue reading "Key Evolutionary Changes: Anatomy, Physiology, and Social Development" »

1. In DNA structure, A always pairs with T. TRUE
2. In DNA structure, cytosine always pairs with adenine. FALSE
3. How many stop codons are there in the genetic code? 3
4. In the genetic code, how many start codons are there? 1
5. In the genetic code, how many naturally occurring amino acids are there? 20
6. Dominant genes are about three times more common than recessive genes. FALSE
7. In this class, Peigler's policy on handheld devices is that they should be turned off and kept out of easy reach. TRUE
8. The traits we studied in the ear of corn were: seed color and plumpness
9. If you cross a white mouse and a black mouse and get gray mice, this is an example of: incomplete dominance
10. Which of the following genotypes is called homozygous dominant? BB
11. Gregor Mendel was a monk

ALLOPHONE: Any possible variation in the production of a phoneme. These variations do not involve any change in the meaning of a word. Allophones are alwaysbased on sounds. Eg: /p/ in “property” and /p/ in “option”

PHONETICS: Science related to the study of the sounds of human speech. Thephysical properties of each one influence the variation of sounds they pronounce. Theunit of phonetics is thesound. The speech processes are:production, transmissions and reception.

  2 STANDARD PRONUNCIATIONS: There are two standard and widely accepted pronunciations:

BBC pronunciation (also called Received Pronunciation, RP in the past) United Kingdom. 

GeneralAmericanpronunciation(GenAm) NorthAmerica. 

2 TYPES OF TRANSCRIPTION:

Internal Environment

Internal environment refers to the fluids that surround the cells in the body. This stable internal environment, called homeostasis, is maintained by the organ systems of the body.

The Circulatory System

The circulatory system consists of the blood circulatory system. It carries nutrients and oxygen throughout the body and collects metabolic wastes for elimination. The lymphatic system has three main functions: transport absorbed fat from the fat, defend the body in the immune system, and return excess interstitial fluid to the blood.

Blood

Blood is a thick red liquid that flows inside the blood vessels. Blood's plasma consists of water and dissolved substances. Blood cells, red and white blood cells, and platelets make up the... Continue reading "Understanding the Internal Environment and Circulatory System" »

21) Osmosis can be defined as

the diffusion of water.

22) A cell that neither gains nor loses water when it is immersed in a solution is

isotonic to its environment.

23) Which of the following processes can move a solute against its concentration gradient?

active transport

24) Which of the following is a typical feature of an ATP-driven active transport mechanism?

The solute moves against the concentration gradient.

25) The process of a white blood cell engulfing a bacterium is

phagocytosis.

26) Which of the following examples is classified as a metabolic pathway?

protein synthesis

27) Which of the following most accurately describes selective permeability?

Only certain molecules can cross a cell membrane.

28) Which of the following would likely move through... Continue reading "Cellular Processes and Energy Production" »

Key Properties of Proteins

• Their molecular weight ranges from 1,000 to several hundred thousand.
• Generally water-soluble, with the exception of hydrophilic membrane proteins.
• Absorb light in the UV range, with maximum absorption at 280nm due to the presence of aromatic amino acids.
• Have a specific isoelectric pH (pI). Positively charged below pI, negatively charged above pI.
• Proteins are charged, which depends on the buffer.
• Move under the electric charge and can be separated by electrophoresis.
• Give a color reaction with reagents, such as a blue color with ninhydrin.

Classification of Proteins

Basis of Structure

1. Globular: All enzymes and intracellular proteins are globular, such as myoglobin and hemoglobin.
2. Fibrous: Mostly extracellular, such as collagen.