Notes, summaries, assignments, exams, and exercises for Biology for Baccalaureate

Mollusks

Triploblasty, coelomates, not segmented. Bilateral symmetry. Soft body (head, visceral mass, foot). Limestone shell. Complete digestive tube (mouth-anus). Radula (in most). Open circulatory system (closed in cephalopods). Excretory system: 1 or 2 metanephridia. Ganglionic nervous system. Asexual or larval reproduction.

• Bivalves: Mussels
• Gastropods: Snails
• Cephalopods: Cuttlefish

Annelida

Triploblasty, coelomates. Bilateral symmetry. Elongated cylindrical body with rings or metamerism. Closed circulatory system. Ganglionic nervous system. Cutaneous respiration. Excretory system: metanephridia. Sexes separate or hermaphrodites. With or without a larval stage.

• Polychaetes: Marine worms
• Oligochaeta: Earthworms
• Hirudinea: Leeches

Arthropods

Triploblasty,...

The Nephron: Structure and Function

The nephron is the functional and anatomical unit of the kidneys. It is responsible for filtering the blood and reabsorbing essential substances.

Nephron Parts:

1. Bowman's Capsule: The end of the nephron is cup-shaped and surrounds a network of capillaries called the glomerulus. The glomerulus is connected to an afferent arteriole (input) and an efferent arteriole (output).
2. Proximal Convoluted Tubule: Named for its serpentine appearance.
3. Loop of Henle: A narrowed area of the proximal tubule, with a descending and an ascending branch.
4. Distal Convoluted Tubule: A continuation of the loop of Henle, it connects with the collecting duct.

The collecting duct empties into the renal pelvis.

Urine Formation

Urine formation takes...

Cytokinesis

Cytokinesis begins in anaphase and continues through telophase.

• In animals: The process involves strangling the cytoplasm. Segmentation is a linear division, resulting in the formation of a contractile ring formed by actin filaments.
• In plants: The cell wall prevents segmentation. This is done by forming a new wall inside the cell. This new wall is formed at the equator by the association of Golgi apparatus vesicles and microtubules, and it is called a phragmoplast. It extends laterally to reach the cell wall.

Types of Cell Division

1. Bipartition

   Division of the cell. Two daughter cells originate, equal in size. The process involves karyokinesis and cytokinesis, with its variant being strangulation.

2. Multiple Fission

   Divisions of the cell.

Intramuscular Drug Administration and Receptor Binding

Explains what a circuit is: a drug that is administered intramuscularly until it reaches the receptor. It exits the bloodstream through the capillary endothelium, traveling through the interstitial fluid, and crosses the cell membrane of its target cells.

Morphine Effects in Elderly Patients

Explains why an old man, who is administered morphine in doses equal to a middle-aged person, may be at increased risk of sleepiness, even after the drug's effects should have worn off. The elderly, like children, have decreased hepatic activity, so the drug takes longer to metabolize and be disposed of by the body, which can cause drowsiness in the case of morphine.

Drug Molecule Characteristics for Barrier

Regulation of Enzyme Activity

Enzymes are the workhorses of cells, catalyzing the thousands of biochemical reactions that keep cells alive and functioning. The activity of enzymes is carefully controlled to ensure that the proper amount of product is produced at the right time.

Why Regulate Enzyme Activity?

There are several reasons why cells need to regulate enzyme activity. First, the concentration of substrates and products can vary widely within the cell. If enzyme activity were constant, the rate of the reaction would also vary wildly, depending on the availability of substrates. Regulation allows the cell to adjust the rate of the reaction to match the needs of the cell.

Second, the cell needs to coordinate the activities of different enzymes...

Early Foundations and Key Milestones in Plant Tissue Culture

The science of plant tissue culture originates from the discovery of the cell, followed by the postulation of cell theory. In 1838, Schleiden and Schwann proposed that the cell is the basic structural unit of all living organisms. They envisioned that a cell is capable of autonomy and, therefore, it should be possible for each cell, if given the right environment, to regenerate into a whole plant. Based on this premise, in 1902, German physiologist Gottlieb Haberlandt for the first time attempted to culture isolated single palisade cells from leaves in Knop’s salt solution enriched with sucrose. The cells remained alive for up to one month, increased in size, accumulated starch,...

Essential Terminology in Human Anatomy and Physiology

Skeletal System and Musculature

• Scapula: A flat, triangular bone that forms the back of the shoulder.
• Tibia: The inner bone of the lower leg.
• Femur: A bone in the leg extending from the pelvis to the knee.
• Ulna: The bone in the forearm located on the side opposite the thumb.
• Radius: The bone in the forearm located on the side of the thumb.
• Humerus: The long bone in the arm running down from the shoulder to the elbow.
• Skull: The bones of the head, which surround the brain and give the head its shape.
• Pelvis: The bones below the abdomen that support the lower back and are connected to the bones of the leg.
• Hip: The joint and surrounding region connecting the leg to the trunk.
• Deltoid: A large muscle

The Cell Cycle

The cell cycle consists of two main phases: interphase and mitosis (M phase) [3].

Interphase

Interphase is further divided into three phases:

1. G1 phase (Gap 1): During this phase, the cell grows in size and carries out normal metabolic activities [4].
2. S phase (Synthesis): In this phase, DNA replication and chromosome duplication occur [4].
3. G2 phase (Gap 2): The cell continues to grow and prepares for cell division [4].

Mitosis (M phase)

Mitosis is the actual phase of cell division and is divided into four stages:

1. Prophase: Chromosomes condense, the nuclear envelope and nucleolus disappear, and spindle fibers start to appear [4].
2. Metaphase: Chromosomes align at the equatorial plate [4].
3. Anaphase: Centromeres divide, and chromatids move towards