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

Mitochondria

Mitochondria are organelles of eukaryotic cells responsible for generating energy through cellular respiration, a process involving enzymes such as ATP synthase. This energy is stored as ATP. They are found in large quantities in the cytoplasm of all eukaryotic cells, including both animal and plant cells.

Structure of Mitochondria

Mitochondria are polymorphic organelles, varying from spherical to elongated, rod-like shapes. They possess a double membrane: a smooth outer mitochondrial membrane and an inner mitochondrial membrane with many internal folds called mitochondrial cristae.

These membranes create two compartments:

• Intermembrane space: The area between the two membranes.
• Mitochondrial matrix: The space defined by the inner membrane.

Glycolysis: Breakdown of Glucose

Preparatory Phase (Energy Investment)

This initial phase requires the cell to invest energy by spending two ATP molecules to phosphorylate glucose. First, glucose is phosphorylated, and then fructose-6-phosphate undergoes phosphorylation. These phosphate transfers are catalyzed by transferase enzymes, specifically kinases, which transfer phosphate groups from ATP.

1. An isomerase enzyme converts glucose-6-phosphate into a ketose, fructose-6-phosphate.
2. Fructose-6-phosphate is phosphorylated again by a kinase, using another ATP, forming fructose-1,6-bisphosphate.
3. Fructose-1,6-bisphosphate is then cleaved into two different 3-carbon phosphorylated isomers: glyceraldehyde-3-phosphate (G3P) and dihydroxyacetone phosphate

Endosymbiotic Theory: The Origin of Eukaryotic Cells

Prokaryotic cells are the primitive form of life on Earth. Eukaryotic cells appeared subsequently, and the Endosymbiotic Theory explains their origin. At a specific moment, independent organisms merged, and the hosted cells became organelles of a new cell type.

Evidence for Endosymbiosis

• Mitochondria: Resemble bacteria, possess their own DNA, RNA, and ribosomes.
• Chloroplasts: Share similar characteristics with mitochondria.
• Cilia and Flagella: Eukaryotic structures are distinct from those of prokaryotes and bacteria.

This process provided oxidative metabolism capacity, allowing anaerobic cells to become aerobic, and enabled photosynthesis.

The Eukaryotic Cell Membrane

The plasma membrane is a continuous...

Pharmacokinetics: Drug Movement in the Body

Pharmacokinetics is the study of all processes that occur from the moment a drug is administered until it is excreted, and how it exercises its effect at a determined concentration during an established time at its site of action.

Key Pharmacokinetic Processes (LADME)

Liberation

Liberation is the process by which the active ingredient of a medication is released from its dosage form. This involves disintegration and dissolution, making it available for absorption into the bloodstream. Some formulations prevent the disaggregation of the drug in the stomach lining to protect the active ingredient from stomach acid, which can also cause a delay in its release.

Absorption

Absorption is the process by which...

Germplasm Conservation and Cryopreservation

In vitro cell and organ culture offers an alternative source for the conservation of endangered genotypes [40]. Germplasm conservation worldwide is increasingly becoming an essential activity due to the high rate of disappearance of plant species and the increased need for safeguarding the floristic patrimony of countries [41].

Tissue culture protocols can be used for preservation of vegetative tissues when the targets for conservation are clones instead of seeds, to keep the genetic background of a crop, and to avoid the loss of the conserved patrimony due to natural disasters, whether biotic or abiotic stress [42]. Plant species which do not produce seeds (sterile plants) or which have ‘recalcitrant’...

1. Introduction

Tissue culture is the in vitro aseptic culture of cells, tissues, organs or whole plant under controlled nutritional and environmental conditions [1] often to produce the clones of plants. The resultant clones are true-to type of the selected genotype. The controlled conditions provide the culture an environment conducive for their growth and multiplication. These conditions include proper supply of nutrients, pH medium, adequate temperature and proper gaseous and liquid environment.

Plant tissue culture technology is being widely used for large scale plant multiplication. Apart from their use as a tool of research, plant tissue culture techniques have in recent years, become of major industrial importance in the area of plant...

What is Agarose Gel Electrophoresis?

Agarose gel electrophoresis is a method used in biochemistry, molecular biology, genetics, and clinical chemistry to separate a mixed population of macromolecules, such as DNA, RNA, or proteins, in an agarose matrix.

Agarose is a natural linear polymer extracted from seaweed that forms a gel matrix via hydrogen bonding when heated in a buffer and allowed to cool. These gels are the most popular medium for separating moderate to large-sized nucleic acids due to their wide range of separation.

How Gel Electrophoresis Works

Gel electrophoresis separates DNA fragments by size in a solid support medium. The process involves:

• Sample Loading: DNA samples are pipetted into sample wells.
• Electrophoresis: An electric current

Variables en la Investigación Científica

La variable independiente es la que se modifica intencionalmente (la cantidad de agua), la variable dependiente es la que se observa y mide como respuesta a la variable independiente (tiempo que tarda en crecer), y las variables de control se mantienen constantes (luz, temperatura) para garantizar que los resultados sean confiables y precisos.

Microscope Slide Preparation Steps

1. Place a drop of water or mounting medium on a clean microscope slide.
2. Add your specimen to the drop.
3. Carefully lower a coverslip onto the specimen, avoiding air bubbles.
4. Seal the edges and label the slide.
5. Observe the specimen under a microscope.
6. Clean up.

Common Bacterial Shapes and Classifications

Bacteria can have various shapes, including:...

Historical Perspectives on Memory

Phrenology and Molecular Theories

Phrenology: Personality determined...

External Anatomy of the Perch

• 1. Head: Structurally supportive and protective.
• 2. Eye: Visual stimuli.
• 3. Nares: Avenue for water to enter the oral cavity.
• 4. Mouth: Made up of the mandible and maxilla.
• 5. Operculum: Covers and protects soft gills.
• 6. Pectoral fin: Used like paddles; assist in direction change.
• 7. Anterior dorsal fin: Serves as a rudder for stability.
• 8. Posterior dorsal fin: Supported by rays; serves as a rudder for stability.
• 9. Caudal fin: Propels the fish through the water.
• 10. Pelvic fin: Assists in stability when swimming.
• 11. Anal fin: Assists in stability when swimming.
• 12. Lateral line: Sensory organ that allows the perch to detect changes in pressure, movement, and vibration.

Internal Skeletal and Sensory Structures

• 13. Gills: