Neck Muscles and Anatomy: A Comprehensive Guide
Neck Muscles
Lateral Neck
Platysma
Source: Wide, thin muscle situated on the side of the neck, below the superficial fascia.
Insertion: Below the subcutaneous tissue of the subclavicular region, up to the bottom edge of the maxilla. Intersects at the midline, and muscle fibers blend into the facial skin.
Action: Draws down the skin of the chin and lower lip (sad expression).
Sternocleidomastoid
Source: Thick muscle extending obliquely from the upper chest to the mastoid process.
Insertion: Formed by two
Read MorePlant Biology & Environmental Science Study Guide
Pre First Certificate: Water Loss, Transport, and Controlled Growth
Key Questions
- What are stomata and guard cells?
- How can we measure water loss in a plant?
- Describe the main principles of Osmosis, Diffusion, and Active Transport.
- How can the growth and shape of plants be affected?
- What is tropism?
- Why are stems ‘positively phototropic’? What does ‘negatively phototropic’ mean? What is auxin?
- What is the difference between hydrotropism and geotropism?
- How can artificial chemicals be used? Why are
Cellular Metabolism: Ingestion, Digestion, Egestion, and Energy Production
Ingestion, digestion and egestion cell
Many nutrients enter cells in its interior, reducing (if applicable) monomers and, sometimes, eliminate waste. By analogy with the digestive processes of an organism, one can speak of ingestion, digestion and egestion phones.
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Ingestion
Ions and small molecules can cross the cell membrane by diffusion or active transport, but the high molecular mass particles must penetrate within the cell by endocytosis.
Some protozoa ingest large objects, such as bacteria,
Lipids, Carbohydrates, Amino Acids & Peptides in Biochemistry
Lipids
Esfingoglucolipids
In sphingolipids, the polar group that binds to the ceramide is a carbohydrate that can be a monosaccharide or a branched oligosaccharide. The sphingolipids are arranged in the outer zone of the plasma membrane with glycoproteins forming the glycocalyx. Depending on the carbohydrate portion, they are classified into:
- Cerebrosides: Consist of a ceramide and a monosaccharide. They are abundant in the membranes of nerve cells in the brain and peripheral nervous system.
- Gangliosides:
Plasma Membrane and Cytoplasm: Structure and Function
Plasma Membrane
The plasma membrane, also known as the cell membrane, is the first layer that surrounds the cell, separating its internal components from the external environment. It is a dynamic structure that allows for changes in cell shape and movement.
Structure
The plasma membrane has a consistent structure across all cells and is closely associated with cytoplasmic organelles. According to the fluid mosaic model proposed by Nicholson, the membrane is primarily composed of a double layer of lipids.
Read MoreThe fascinating process of photosynthesis
Hypothesis: Autotrophs
Various circumstances led to the appearance and development of autotrophs, including:
A. – Initiation of Photosynthesis
As primitive organisms multiplied, the substances available to them in the seas decreased, leading to increased competition. Organic synthesis likely continued to occur in the atmosphere, but too slowly to restore equilibrium in the consumption of energy reserves in the seas.
Under these conditions, any variation that allowed an organism to manufacture its own
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