Exploring DNA, Genetics, and the Human Genome Project
DNA, Genes, and Proteins
Key Concepts
- DNA (Deoxyribonucleic Acid): A molecule composed of four repeating units (cytosine, guanine, thymine, and adenine) combined in various sequences.
- Nucleotides: The building blocks of DNA, consisting of a phosphate group, a sugar, and a nucleobase.
- Proteins: Essential molecules for life, formed by chains of amino acids. There are 20 different amino acids.
- Gene: A segment of DNA that codes for a specific protein. It’s the basic unit of genetic information.
- Karyotype:
Osmosis, Carbohydrates, Lipids, and Proteins in Cells
Osmosis: Diffusion of Water
Osmosis is the movement of water from a hypotonic (diluted, more water) medium to a hypertonic (concentrated, less water) medium across a semi-permeable membrane. Water moves until the concentrations are equal (isotonic), and osmosis stops.
Osmotic Processes in Cells:
Cells are surrounded by isotonic media to prevent harmful osmotic processes. Animal cells are more sensitive due to their thin plasma membrane.
Processes Affecting Cells:
1. Plasmolysis: Occurs when a cell is
Read MoreEthylene and Polyamines: Plant Growth Regulators
UNIT 20 – Ethylene and Polyamines
Definitions
Methionine: An amino acid formed from S-adenosylmethionine (SAM), a precursor in metabolic pathways, including ethylene and polyamine biosynthesis.
Ethylene: A developmental regulatory molecule (hydrocarbon, C2H4) in plants and animals. It has a simple chemical structure and is active in gaseous form. Its effects occur at very low concentrations and are evident in virtually all life cycle stages.
Triple Response: Ethylene’s effect in seedlings, causing reduced
Read MoreCell Biology and Nutrition Essentials
ITEM 1 Cell Parties
Mitochondria
Oval organelles that provide energy.
Reticulum
Sacks and interconnected channels where proteins and lipids are produced.
Vacuoles
Contain water and dissolved substances.
Lysosomes
Transform substances into simpler ones.
Cytoskeleton
Complex filaments forming a network.
Centrioles
Two hollow cylinders with walls formed by filaments.
Ribosomes
Small particles, free or attached, that manufacture proteins.
Golgi Apparatus
Stacks of membranous sacs that package substances manufactured
Read MoreBiological Classification & Tissue Types
Classification of Animals
Util-harmful-redundant.
Classification of Plants
Production of fruits, vegetable producers, or wood fiber producers.
Carl Von Linné described plant and animal species in SYSTEMA NATURAE.
Ernst Haeckel proposed the Protista kingdom:
Higher Protista (eukaryotic): algae, fungi, protozoa
Lower Protista (prokaryotes): bacteria
Robert Whittaker:
Prokaryotic or Monera: bacteria, archaea
Protista: fungi, mucous protozoa, some algae
Unicellular fungi: yeast; Multicellular fungi: fleshy mushroom
Plantae:
Human Skin Structure and Functions
Human Integumentary System
The integumentary system, or skin, weighs over 3-4 kg and covers about 1.5-2 m2. It’s the body’s largest organ, composed of distinct layers.
Skin Histology
The skin has three main layers:
- Epidermis: Squamous epithelial tissue made of flat cells forming a continuous layer. It’s stratified with multiple layers that keratinize.
- Dermis: Connective tissue providing mechanical support and protection.
- Hypodermis: Subcutaneous adipose tissue (not always considered a skin layer).