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

Protein Synthesis and Protein Structure

Definition of Proteins

Proteins are large molecules formed by the union of amino acids. There are 20 unique amino acids, of which 8 are considered essential because they cannot be synthesized by living organisms. Proteins differ from each other based on the specific order (sequence) of these amino acids.

Functions of Proteins

• They form part of cellular structures.
• They are involved in cellular metabolism.

The Synthesis Process (Gene Expression)

Protein synthesis occurs in two main phases:

1. Transcription: Information transfer from DNA to mRNA (occurs in the nucleus).
2. Translation: Information transfer from mRNA to Protein (occurs in the cytoplasm, involving ribosomes).

Transcription: DNA to mRNA

Genetic information... Continue reading "Molecular Mechanisms of Gene Expression and DNA Replication" »

What is Genetic Engineering?

Genetic engineering is the direct modification of an organism’s genome, which is the list of specific traits (genes) stored in the DNA. Changing the genome enables engineers to give desirable properties to different organisms. Organisms created by genetic engineering are called genetically modified organisms (GMOs).

What is Biotechnology?

Biotechnology is the use of organisms and their genetics in industries to make products.

How is it Possible?

Because all living organisms have DNA, by moving DNA from one organism to another, it is possible to transfer different traits.

The GMO Process

• All genetic changes affect the protein synthesis of the organism.
• By changing which proteins are produced, genetic engineers can affect

The Human Nervous System: Divisions and Functions

The human nervous system is a complex network responsible for controlling all body activities. It is broadly divided into two main parts:

• Central Nervous System (CNS): Protected by bones (skull and spine) and three membranes called meninges.
• Peripheral Nervous System (PNS): Composed of nerves that connect receptors and effectors to the central nervous system.

Central Nervous System (CNS)

The Central Nervous System (CNS) is the body's control center, formed by the brain (located inside the skull) and the spinal cord (located inside the spine).

The Brain: Control Center of the Body

The brain is the most complex organ in the human body, responsible for thought, emotion, memory, and movement. It comprises... Continue reading "Human Nervous System: Central and Peripheral Divisions" »

__________ 1. In sexual reproduction of fungi, spores are produce By mitosis.

__________ 2.Yeast is a rapidly growing, asexually reproducing Stage of some types of fungi.

__________ 3.Fungi form mutualistic symbiotic associations with Other organism.

__________ 4.Fungi play important ecological roles by decomposing Organic matter and by

breaking down and absorbing minerals From rocks and soil.

__________ 6.All fungi are helpful.

__________ 7.Plants are multicellular eukaryotes whose cells have cell membrane made of

cellulose.

__________ 8.Reproduction in seed plants is characterized by a Greatly reduced gametophyte

and a dominant sporophyte.

__________ 9. The flowers of many gymnosperms are adapted for Pollination by wind or by

animals.

__________ 10.Although... Continue reading "JHH-7 doubling time" »

Burnt: a lesion xl'efecte increased temperature

• Thermal: xcontacte with a heat source
  • chemical x contact a chemical agent, acid or base.
  • Electrical: 1 x touch with electrical source.

Severe burns the skin ceases to fulfill its protective function, the affected area loses body fluids

Assessment of burns:

• Extension: body surface area affected, and if the burn is extensive loss of fluid can produce a significant decrease in blood volume (hypovolemic shock.) Location and extent: determining the complications affecting the area of the body determines the severity of injury.
  • Depth: determines the evolution (layers involved)
  • First grade: + surface layer of skin (epidermis)
  • Second degree: epidermis and all or part of the dermis
  • Receiving NO BOTTLES

Invertebrate Excretory Mechanisms

Simplest animals: Excretion occurs by direct diffusion through the skin.

• Protonephridium: Found in Platyhelminthes (flatworms) and annelids. This is a closed system consisting of two highly branched duct systems distributed throughout the body. At the closed ends, waste molecules are taken up by ciliated cells (flame cells); at the open end, they feature a pore (nephridiopore) for waste elimination.
• Metanephridium: Found in annelids and molluscs. This consists of a tube that allows fluid to enter the tubule through a ciliated, funnel-like opening. It is surrounded by blood vessels that reabsorb water, salts, sugars, and amino acids.
• Antennal glands: Found in crustaceans. Located in the ventral part of the head,

Human Skeletal System: Key Structures and Functions

Types of Synovial Joints

• Plane Joints

  Characterized by flat surfaces on one bone meeting with flat surfaces of another, allowing for slipping and gliding movement with no axial rotation. Common examples include the carpal bones of the wrist.

• Hinge Joints

  A cylindrical projection of one bone fits into a trough-shaped surface of another bone. These joints permit flexion and extension, like the elbow joint (specifically, the olecranon process of the ulna).

• Pivot Joints

  A rounded projection of one bone fits into a rounded depression or sleeve of another bone, often held together by ligaments. They allow for uniaxial movement, such as the rotation of the odontoid process of C2 (axis) within the anterior