Proteins Overview Quiz

Protein Types

• Fibrous Proteins: Long strands providing mechanical support and tensile strength; can contract and return to original length. Examples: collagen and muscle proteins.
• Globular Proteins: Compact and spherical; biologically active, involved in transporting molecules, immune responses, and regulating growth and development.
• Enzymes: Biological catalysts that lower activation energy for reactions; can be highly specific or act on multiple substrates; crucial for sustaining biological processes.

ATP & Cellular Energy

• Adenosine Triphosphate (ATP): Primary energy-transfer molecule in cells; oxygen is required for ATP production.
• Triphosphate Tail: Contains high-energy bonds; transferring a phosphate group to another molecule grants it temporary energy, which is lost once work is done.
• Energy Dynamics: ATP storage and release are essential for driving chemical reactions in cells, highlighting the transient nature of ATP.

Plasma Membrane Structure

• Fluid Mosaic Model: Describes the plasma membrane as a phospholipid bilayer with randomly dispersed proteins, which is mainly impermeable to water-soluble molecules.
• Functions: Separates intracellular fluid (ICF) from extracellular fluid (ECF).

Chemical Composition of Cell Membranes

• Lipids:

  • Phospholipids: Form the membrane's foundation; features hydrophilic phosphate heads and hydrophobic fatty acid tails, crucial for membrane resealing.
  • Cholesterol: Stabilizes the membrane structure while maintaining flexibility.

• Proteins:

  • Integral proteins span the membrane; major roles include transport, enzyme functions, and cell recognition.
  • Peripheral proteins are loosely attached and largely serve as enzymes and structural components.

• Carbohydrates: Coat the extracellular surface, forming glycocalyx; involved in cell recognition and tissue identification.

Cell Junctions

• Function: Connect or adhere cells together.
• Types of Junctions:
  • Tight Junctions: Seal adjacent cells, maintaining the environment balance and communication.
  • Receptor-Mediated Endocytosis: Specific intake of substances through receptor binding.
  • Exocytosis: Process of transporting substances out of the cell through vesicles.
  • Transcytosis: Movement into, across, and out of a cell, facilitating transport through tissues.
  • Vesicular Trafficking: Transfers substances within the cell without leaving it.

Membrane Potential

• Resting Membrane Potential: Average of -70 mV; characterized by a charge difference across the membrane, with a more negative inside.
• Ion Balance: High concentration of Na+ outside and K+ inside; K+ channels are leakier, influencing membrane potential.
• Active Transport: Maintains ion gradients, ensuring the cell's resting potential is stable amidst Na+ leakage.

Plasma Membrane Receptors

• Role: Enable cell-environment interactions through ligand binding.
• Contact Signaling: Cells recognize each other through physical contact; significant for growth and immunity.
• Chemical Signaling: Ligands bind to receptors, triggering intracellular responses; one ligand can result in multiple cellular changes.

Tissues Overview

• Definition: Groups of similar cells performing common functions; essential for organ complexity and function.
• Types of Tissue:
  • Nervous: Control functions, encompassing neurons and supportive cells.
  • Muscle: Facilitates movement; consists of skeletal, cardiac, and smooth muscle types.
  • Epithelial: Forms coverings and lines cavities; can be covering or glandular epithelium.
  • Connective: Provides structural support.

Nervous Tissue

• Function: Regulates body functions through electrical impulse transmission.
• Cell Types:
  • Neurons: Generate and transmit impulses.
  • Supporting Cells: Offer protection and support to neurons.

Muscle Tissue

• Movement: Enables voluntary and involuntary actions; contraction arises from actin and myosin filaments.
• Types:
  • Skeletal: Voluntary with striations, attached to bones.
  • Cardiac: Involuntary, striated, located in the heart.
  • Smooth: Involuntary, non-striated, found in hollow organs.

Epithelial Tissue

• General Functions: Forms boundaries and regulates substance passage.
• Types:
  • Covering Epithelium: Lines external and internal surfaces.
  • Glandular Epithelium: Comprises the glands of the body.
• Apical Surface: Faces open spaces, critical for function and interaction.### Jaundice and Genetic Disorders
• Jaundice indicates liver failure, characterized by yellowing of the skin and eyes.
• Albinism results in a lack of pigmentation, leading to red or pink eyes due to visible blood vessels.
• Argyria is a condition caused by excessive silver consumption, resulting in a blue discoloration of the skin.

Skin Appendages

• Skin appendages include structures associated with skin but are not skin itself.

Hair (Pili)

• Hair grows from follicles and is composed of dead, keratinized cells.
• Root: embedded in the skin, protects against loss.
• Shaft: visible part of hair projecting out of the skin.
• Functions include sensory perception and protection from UV light and debris.
• Hair structure consists of three layers:
  • Medulla: central core; absent in thin hair.
  • Cortex: several layers of flattened cells; prevents excessive thickness.
  • Cuticle: outermost layer with heavily keratinized cells arranged like shingles.

Structures Associated with Hair

• Hair Follicle: extends from epidermis into dermis with three layers, providing structure and support.
• Root Hair Plexus: nerve endings at the base of the hair bulb, enabling sensation.
• Dermal Papilla: supplies capillaries necessary for hair growth.
• Arrector Pili: smooth muscle associated with each hair follicle; causes goosebumps.

Hair Characteristics

• Hair shape is determined by the follicle: round for straight, oval for wavy, flattened for curly hair.
• Hair color is due to melanin in the cortex; pheomelanin results in red hair, while gray or white occurs with aging due to decreased melanin.

Hair Growth Phases

• Hair matrix: rapidly dividing cells in the hair bulb.
• Growth phase: active cell division; old cells pushed upward.
• Resting phase: inactive; hair remains in the follicle.
• Shedding phase: hair detaches from the follicle.

Types of Hair

• Vellus hair: fine, thin hair, more common in children and females.
• Terminal hair: thick, coarse hair, prevalent in adults, especially in males.

Hair Loss and Baldness

• Hair thinning is common with age; hair loss can exceed replacement.
• Male-pattern baldness is linked to genetic factors and androgen hormones.

Nails

• Nails are located at the tips of fingers and toes, composed of hard keratinized cells.
• Structure: root, nail plate, free edge; nail growth occurs in the nail matrix.

Skin Glands

Sweat Glands

• Composed of myoepithelial cells that contract to aid in sweat secretion.
• Sweat contains water, salts, and metabolic wastes.

Burns

• 1st Degree: painful, reddened skin; no scarring.
• 2nd Degree: pain, blisters, longer healing time; minimal scarring if not disturbed.
• 3rd Degree: full-thickness burn affecting all skin layers; requires significant medical intervention and can lead to dehydration.

Bone and Skeletal Tissue

• Functions of bones encompass support, protection, attachment for muscles, mineral and fat storage, blood cell formation, and hormone production.

Types of Cartilage

• All cartilage features chondrocytes.
• Hyaline cartilage: most abundant type; found in joints and respiratory structures.
• Elastic cartilage: similar to hyaline, with more elastic fibers; found in the ear and epiglottis.
• Fibrocartilage: provides tensile strength; found in vertebral discs and knee joints.

Types of Cartilage Growth

• Appositional growth: new cartilage is added to the surface.
• Interstitial growth: chondrocytes divide, secreting matrix within existing cartilage.

Test your knowledge about the two main types of proteins: fibrous and globular. This quiz covers their structures, functions, and examples to help you understand the role of proteins in biology. Dive in to assess your understanding of these essential biomolecules.