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

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.

Neurology: Anatomy and Physiology Fundamentals

Anatomy of the Nervous System

Central Nervous System (CNS)

• Brain: Cerebrum, Diencephalon, Cerebellum, Brain Stem
• Spinal Cord

Peripheral Nervous System (PNS)

• Spinal Nerves
• Peripheral Nerves

Supporting Structures

• Meninges: Membranes surrounding the brain and spinal cord
• Cerebrospinal Fluid (CSF)

Physiology of the Nervous System

Peripheral Nervous System (PNS) Functions

• Autonomic Nervous System:
  • Sympathetic (Adrenergic)
  • Parasympathetic (Cholinergic)
• Somatic Nervous System

Central Nervous System (CNS) Functions

• Cerebrum & Diencephalon: Higher cognitive functions
• Cerebellum: Helps with movement coordination
• Brain Stem: Regulates vital functions like temperature, blood pressure, and heart rate

Common Neurological Signs

Blood: Functions and Composition

Blood is a type of connective tissue. It is a thick red liquid made up of specialized cells suspended in a watery solution of molecules and ions. Blood transports nutrients and oxygen to the cells and carries waste residues to where they can be eliminated. Besides that, it regulates body temperature, pH and water volume, transports hormones, and defends our body from infections or from excessive blood loss when we get wounded. Blood is the only liquid tissue in our body because the matrix in which blood cells are immersed is liquid. The liquid component of blood is called plasma and it represents about 55% of blood volume.

Plasma: Composition and Role

Plasma is a pale yellow liquid. About 90% of it is water. The... Continue reading "Human Blood: Composition, Functions, Cardiac Cycle & Edema" »

Auto or Self Antigens

Antigens present in one's own cells.

Altered by the action of bacteria, viruses, chemicals, or drugs as a non-self.

Auto antibody

Altered cell (Auto Ag) - elicits the production of Antibody.

Autoimmunity (misnomer, alternative = auto allergy)

Immune response of auto Ab against self Ag.

Humoral or cell-mediated immune response against the constituents of the body's own tissues.

There are more than 80 different kinds of diseases caused by autoimmunity.

Causes of Autoimmune Diseases

Sequestered or Hidden antigens

Ag in the secluded places - are not accessible to the immune system.

Neo antigens

Altered or Modified Antigens – by physical (irradiation), chemical (drugs), or microbial agents (intracellular viruses).

Cessation of Tolerance

It... Continue reading "Auto or Self Antigens: Causes and Effects of Autoimmunity" »

Behind the iris is a lens which changes shape in order to focus the image.