MBS Lecture 2 Flashcards
What is the size of a typical cell
0,1 mm
When was the invention of the telescope
17th century
Who inspected thin slides of cork
ROBERT HOOKE
What did Robert Hooke discover?
millions of small, irregular units
What is the cell theory?
- All cells come from a division of pre-existing cells
- Cells are the building blocks for plants and animals
- Cells are the smallest unit that perform all vital physiological functions
- Each cell maintains homeostasis at the cellular level. Homeostasis at the level of the tissue, organ, organ system, and organism reflects the combined and coordinated action of many cells
What are cells surrounded by?
A watery medium, extracellular fluid (interstitial fluid)
What does the plasma membrane do?
Separates the cytoplasm from the extracellular fluid
What is inside the cytoplasm?
Cytosol
What is inside the cytosol?
Organelles
What are intracellular structure?
Organelles
What are the functions of the plasma membrane?
Physical isolation
- Barrier
Regulates exchange with environment
- Ions and nutrients enter
- Wastes eliminated and cellular products released
Monitors the environment
- Extracellular fluid composition
- Chemical signals
Structural support
- Anchors cells and tissues
What is inside the plasma membrane?
Membrane lipids, proteins and carbohydrates
What are membrane lipids?
Double layer phospholipid molecules
What do phospholipid molecules contain?
Hydrophylic and hydrophobic heads
What do hydrophilic heads do?
They move toward watery environment, both sides
What do hydrophobic tails do?
They are fatty acid tails that are inside the membrane
They are a barrier to ions and water—soluble compounds
Which is polar?
The hydrophilic (polar) head is soluble in water
Which is nonpolar?
They have two hydrophobic (nonpolar) tails are not. A tail
has a kink wherever there is an unsaturated bond.
What do phospholipids form?
Phospholipids form a bilayer that serves as the major
component of a cell’s plasma membrane. The fluidity of the
plasma membrane is due to kinks in the phospholipids’
tails
Types of Membrane proteins:
Integral and Peripheral
Where are Integral and Peripheral Proteins?
Within the membrane
Bound to inner or outer surface of the membrane
What are the different types of proteins?
Anchoring proteins (stabilizers)
- Attach to inside or outside structures
Recognition proteins (identifiers)
- Label cells as normal or abnormal
Enzymes
- Catalyze reactions
Receptor proteins
- Bind and respond to ligands (ions, hormones)
Carrier proteins
- Transport specific solutes through membrane
Channels
- Regulate water flow and solutes through membrane
What are the most important abundant organic
molecules?
Proteins
What do proteins contain?
Carbon (C), hydrogen (H), oxygen (O), and nitrogen (N)
How many basic building blocks do proteins
have
20 amino acids
What are the 7 major protein functions?
Support
- Structural proteins
Movement
- Contractile proteins
Transport
- Transport (carrier) proteins
Buffering
- Regulation of pH
Metabolic regulation
- Enzymes
Coordination and control
- Hormones
Defense
- Antibodies
What is the structure of proteins?
Long chains of amino acids
Amino acid structure: Central carbon atom, Hydrogen
atom, Amino group (—NH2), Carboxylic acid group
(—COOH), Variable side chain or R group
What are the building blocks of proteins?
Amino Acids
What do all amino acids have in common?
The acidic carboxyl group
What distinguishes amino acids?
The different R groups, which gives each amino acid its own chemical properties
What are Proteoglycans, glycoproteins, and glycolipids made of?
Pro+carbs - Carbs+Pro - Carbs+lipids
Where are they found?
They extend outside cell membrane
What do they form?
They form sticky “sugar coat” (glycocalyx)
What are the functions of glycocalyx?
Lubrication, Protection, Anchoring, Locomotion, Specificity in binding (receptors) and Recognition (immune response)
What are Lipids?
Mainly hydrophobic molecules such as fats, oils, and waxes
What atoms are lipids made of?
They are made mostly of carbon and hydrogen atoms
What do fatty acids contain?
Long chains of carbon and hydrogen with a carboxylic acid group (COOH) at one end
Are fatty acids polar or nonpolar?
They are relatively nonpolar, except the carboxylic group
What can fatty acids be?
Saturated or unsaturated
Saturated
They have hydrogen (no covalent bonds)
Unsaturated
(one or more double bonds):
- monounsaturated = one double bond
- polyunsaturated = two or more double bonds
What do Phospholipids and Glycolipids have?
Diglycerides attached to either a phosphate group (phospholipid) or a sugar (glycolipid)
What do BOTH Phospholipids and Glycolipids have?
They generally, both have hydrophilic heads and
hydrophobic tails and are structural lipids, components of plasma (cell) membranes
Where are Organelles and cytoplasm found?
Inside the cell and outside the nucleus
What does the cytosol do?
Dissolved materials: nutrients, ions, proteins, and waste
What nutrients are in the cytosol
High potassium/low sodium
High protein
High carbohydrate/low amino acid and fat
What are organelles?
Structures with specific functions
What are nonmembranous organelles?
- No membrane
- Direct contact with cytosol
- Includes the cytoskeleton, microvilli, centrioles, cilia, ribosomes, and proteasomes
What are membranous organelles?
- Covered with plasma membrane
- Isolated from cytosol
- Includes the endoplasmic reticulum (ER), the Golgi
apparatus, lysosomes, peroxisomes, and mitochondria
Example of a nonmembranous organelle:
The cytoskeleton
What does the cytoskeleton do?
They are structural proteins for shape and strength
Types of cytoskeleton:
Microfilaments
Intermediate filaments
Microtubules
What are microfilaments?
Thin filaments composed of the protein actin
What is the function of microfilaments?
- Provide additional mechanical strength
- Interact with proteins for consistency
- Pair with thick filaments of myosin for muscle
movement
What is the function of intermediate filaments?
- Provide strength
- Stabilize position of other organelles
What is the function of microtubules?
- Provide cell strength, rigidity; anchor organelles
- Alter shape of cell; assist in cell movement
- Align and move organelles within the cell
- Form the mitotic apparatus for cell division
- Form centrioles, cilia, and flagella
