Understanding Ecosystems: Biotope, Biocenosis, and Biosphere
Omnivores include wild boars, chimpanzees, pigs, and humans. Every living thing depends on others for sustenance. Herbivores depend on plants, and carnivores depend on herbivores. To express the power relations in a group of living beings, we use diagrams called food chains.
Ecosystem Studies
Ecosystem studies involve:
- The interaction between organisms (who eats whom)
- Types of feeding (what they eat, how they reproduce)
- Their relationship with the environment (what happens when it’s hot, when there’s
Central and Peripheral Nervous System: Functions and Health
Central Nervous System
The central nervous system is formed by the spinal cord and brain. It is protected by the skull, spine, and meninges. Between the meninges is the cerebrospinal fluid. It has two zones:
- The gray matter is formed by cell bodies and dendrites.
- The white matter is formed by axons covered by myelin.
Spinal Cord
The spinal cord is a nerve cord that runs inside the spine. The gray matter is in the center, and the white matter is outside. Within the gray matter, there is a tube called
Read MoreEndoplasmic Reticulum and Centrosome: Structure, Function, and Roles
Endoplasmic Reticulum (ER)
The endoplasmic reticulum (ER) is an intracellular membranous system located between the plasma membrane and the nuclear envelope. Its membrane is continuous with the nuclear membranes. This divides the cytosol into two compartments: the luminal space (inside the ER) and the cytosolic space (outside the ER).
Rough Endoplasmic Reticulum (RER)
The RER has ribosomes attached to the cytosolic side of its flattened membranes. It consists of interconnected sacs or cisternae and
Read MoreHow Digestive, Respiratory, and Circulatory Systems Work
Digestive System
Overview
The digestive system processes food, converting it into simpler substances that the body can absorb. These nutrients then pass into the bloodstream to nourish the body’s cells.
Digestive Tract
The digestive tract is a 10-meter long duct consisting of the mouth, pharynx, esophagus, stomach, small intestine, large intestine, and anus.
Digestive Glands
Digestive glands secrete substances necessary for breaking down food. These glands include the salivary glands, liver, and pancreas.
Read MoreCellular Respiration and Photosynthesis: Key Concepts
Photosynthesis and Cellular Respiration
Key Questions and Answers
Photosystem 1
What is produced in Photosystem 1?
P700
Photosystem 2
What is produced in Photosystem 2?
P680
Light Reaction
Photosystem I & II are part of what reaction?
Light reaction
ATP Production
In animal cells, what organelle produces ATP?
Mitochondria
Glycolysis
Where does glycolysis occur?
Cellular respiration – cytoplasm of the cell
Energy Source for Photosynthesis
What is the energy source for photosynthesis?
The Sun
Calvin Cycle
How would
Read MoreCellular Structures and Functions: A Detailed Look
Ribosomes
Ribosomes are either free in the cytosol or bound to the rough endoplasmic reticulum (RER), the external nuclear membrane, and inside chloroplasts and mitochondria. They are formed by two subunits: the small subunit and the large subunit. Ribosomes have two active sites:
- P (peptidyl) site: Where the first aminoacyl-tRNA carrying the first methionine codon is placed.
- A (aminoacyl) site: Where the second codon is placed.
Ribosomes synthesize proteins.
Peroxisome
Peroxisomes are located near the
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