Cell Biology: Structure and Function
Cell Theory
Postulates of the cell theory:
- All living organisms are composed of one or more cells.
- The cell is the basic structural, functional, and physiological unit of life.
- All cells arise from pre-existing cells through cell division.
- Hereditary material, containing the genetic characteristics of a cell, is passed from parent cell to daughter cell.
Prokaryotic Cells
Prokaryotic cells are typically small and possess a cell wall with a variably composed membrane. They lack a true nucleus, sometimes
Read MoreNutrition Fundamentals: Nutrients and Their Roles
Diet and Nutrition
Nutrition
Concept: Nutrition is the science of food, nutrients, and their actions, interactions, and balance for health and disease. It also deals with the social, economic, cultural, and psychological aspects of food. It can be defined as an involuntary process that begins after food ingestion, providing energy, building and repairing body structures, and regulating metabolic processes.
Food: Food is the set of actions that provide the body with the raw materials necessary for life
Read MorePhotosynthesis and Chemosynthesis Processes
– Phase Cyclic Light:
Intervenes only in PSI, resulting in the synthesis of ATP. Because PSII is not involved, nor is photolysis, consequently, there is no oxygen production or clear reduction of NADP+. The aim of the cyclic phase is to solve the ATP deficit found in the acyclic phase to carry out the subsequent dark phase. The cyclic phase occurs when illuminated with light of a wavelength greater than 680nm, called far-red.
– Phase Dark Biosynthetic
It consists of the addition of CO2 to a sugar called
Read MoreCell Structure, Metabolism, and Division: Essential Concepts
Cell: The Building Block of Life
The cell is the fundamental functional and morphological unit of all living things.
Eukaryotic Cell
All eukaryotic cells, including plant and animal cells, have membrane-enclosed compartments (organelles) within their cytoplasm where specific chemical reactions occur. Their hereditary material is contained within a nucleus.
Cell Morphology
Cells vary in shape, often spherical, depending on their function or lack thereof.
Plasma Membrane
The plasma membrane is a single,
Read MoreHuman Body Systems: Nervous, Excretory, Digestive, Respiratory
Nervous System: Cells
The nervous system is composed of neurons and glial cells. Neurons transmit nerve impulses and do not regenerate. A neuron consists of a cell body, dendrites, and an axon. The space between neurons is called a synapse, where neurotransmitters facilitate communication. Nerve impulses travel from the cell body to the axon.
Types of Neurons:
- Sensory (afferent) neurons: Carry information from receptors to the central nervous system.
- Interneurons: Exist within the central nervous system
Chromosome Alterations and Genetic Engineering Techniques
Chromosomal Alterations
Structural Alterations
These affect the structure of chromosomes, impacting gene location. They are usually caused by errors in mitosis and meiosis, mainly affecting homologous chromosome pairing during prophase I. There are four types:
- Deficiencies or Deletions: Loss of a chromosome segment, affecting multiple genes. Example: Cri du chat syndrome.
- Duplications: Repetition of a chromosome segment, often in heterozygous series. Cytologically recognized during mating as a duplicated