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Questions and Answers
What is the primary function of functional proteins in a cell?
What is the primary function of functional proteins in a cell?
Which of the following accurately describes prokaryotic cells?
Which of the following accurately describes prokaryotic cells?
What distinguishes Gram-positive bacteria from Gram-negative bacteria?
What distinguishes Gram-positive bacteria from Gram-negative bacteria?
What is the primary role of cells in living organisms?
What is the primary role of cells in living organisms?
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What are nucleotides primarily composed of?
What are nucleotides primarily composed of?
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Which of the following accurately describes the composition of a cell?
Which of the following accurately describes the composition of a cell?
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What roles do commensal bacteria play in the human body?
What roles do commensal bacteria play in the human body?
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Which statement about adenosine triphosphate (ATP) is true?
Which statement about adenosine triphosphate (ATP) is true?
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What process allows cells to produce copies of themselves?
What process allows cells to produce copies of themselves?
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How do animal cells primarily obtain energy?
How do animal cells primarily obtain energy?
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What is one of the three main functions of a cell?
What is one of the three main functions of a cell?
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What distinguishes prokaryotic cells from eukaryotic cells?
What distinguishes prokaryotic cells from eukaryotic cells?
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Which statement about cells is false?
Which statement about cells is false?
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What process do plant cells use to obtain energy?
What process do plant cells use to obtain energy?
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What is a key feature of cellular organization?
What is a key feature of cellular organization?
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What percentage of most cells, excluding fat cells, is composed of water?
What percentage of most cells, excluding fat cells, is composed of water?
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Which type of bond holds water molecules together?
Which type of bond holds water molecules together?
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What term is used to describe molecules that easily dissolve in water?
What term is used to describe molecules that easily dissolve in water?
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What are ions?
What are ions?
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What is the simplest form of sugar called?
What is the simplest form of sugar called?
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How is glucose stored in the body?
How is glucose stored in the body?
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What kind of molecules do not form hydrogen bonds with water?
What kind of molecules do not form hydrogen bonds with water?
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What is the primary role of glucose in cells?
What is the primary role of glucose in cells?
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Which functional group is likely to make a molecule hydrophilic?
Which functional group is likely to make a molecule hydrophilic?
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What type of bond links monosaccharides together to form larger carbohydrates?
What type of bond links monosaccharides together to form larger carbohydrates?
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What is the primary function of mitochondria in cells?
What is the primary function of mitochondria in cells?
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What process is guided by the mRNA sequence?
What process is guided by the mRNA sequence?
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What do nucleotides in DNA consist of?
What do nucleotides in DNA consist of?
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What is involved in the process of transcription?
What is involved in the process of transcription?
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What process do cells undergo to create genetically identical copies?
What process do cells undergo to create genetically identical copies?
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What is a function of the DNA within cells?
What is a function of the DNA within cells?
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What is released as a result of cellular respiration?
What is released as a result of cellular respiration?
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During DNA replication, what happens to the two strands of the DNA helix?
During DNA replication, what happens to the two strands of the DNA helix?
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Which of the following substances are involved in the chemical reactions within cells?
Which of the following substances are involved in the chemical reactions within cells?
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Which nitrogenous base is not found in DNA?
Which nitrogenous base is not found in DNA?
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What are the main components of triglycerides?
What are the main components of triglycerides?
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What property does the long hydrocarbon chain of fatty acids give them?
What property does the long hydrocarbon chain of fatty acids give them?
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Which lipid type is primarily responsible for forming the cell membrane?
Which lipid type is primarily responsible for forming the cell membrane?
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What is one primary function of triglycerides in the body?
What is one primary function of triglycerides in the body?
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Which component is not present in the structure of an amino acid?
Which component is not present in the structure of an amino acid?
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What percentage of the cell's mass do phospholipids and cholesterol constitute?
What percentage of the cell's mass do phospholipids and cholesterol constitute?
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Which of the following describes the process by which proteins are formed?
Which of the following describes the process by which proteins are formed?
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What role do fatty acids play in cellular energy production?
What role do fatty acids play in cellular energy production?
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Which structure is primarily formed from the folding of a polypeptide chain?
Which structure is primarily formed from the folding of a polypeptide chain?
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What type of molecules are lipids considered to be?
What type of molecules are lipids considered to be?
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Study Notes
Cellular & Molecular Biology MD105
- Course taught by Dr. Michaeloudes
- Offered by the European University Cyprus School of Medicine
Lecture Objectives
- Understanding cells and their functions
- The major chemical components within cells
- The diverse morphologies and functions of cells
- Differentiating prokaryotic and eukaryotic cells
What is a cell?
- Smallest unit capable of performing life functions
- Membrane-enclosed, filled with concentrated, aqueous solution of chemicals
- Capable of self-replication via growth and division
Cells are the fundamental units of life
- Living organisms (sea urchin, mouse, seaweed) are diverse
- All living things are created from cells
The main functions of a cell
- Generating energy (all cellular activities)
- Animal cells: energy from food (chemical bonds)
- Plant cells: energy from sunlight
- Synthesizing proteins (all cellular functions)
- Cell structure, enzymes, signaling molecules, receptors
- Making more cells (growth and repair)
Cells generate energy by breaking down nutrients
- Cells break down nutrients (glucose/fatty acids) with oxygen to produce energy
- This occurs in mitochondria yielding adenosine triphosphate (ATP)
The instructions for all the cell's functions are stored in the DNA
- DNA stores hereditary information like computers on a hard drive/cloud
- DNA is a long polymer chain made of nucleotides
- Nucleotides contain 4 different nitrogenous bases (adenine, guanine, thymine, cytosine)
The DNA code provides the instructions for making proteins
- DNA sequence guides mRNA synthesis (Transcription)
- mRNA sequence guides protein synthesis (Translation)
Cells make identical copies of themselves
- Cells duplicate DNA and divide into two identical daughter cells
- Used for growth and damage repair
Cells can accurately duplicate DNA
- The two DNA strands are pulled apart as templates for creation of matching strands
The chemical composition of cells
- Cells are composed of water, ions, amino acids, sugars, fatty acids, and nucleotides
Water
- Most cells contain much water (70-85%)
- Water molecules are polar with an uneven distribution of electrons
- Held together by hydrogen bonds
- Water dissolves polar molecules (hydrophilic)
Hydrophilic molecules
- Dissolve easily in water (water-loving)
- Polar or charged molecules that form hydrogen bonds with water
- Examples include: hydroxyl, carbonyl, carboxyl, and amino groups
Hydrophobic molecules
- Don't dissolve in water (water-fearing)
- Non-polar/uncharged molecules
- Examples: hydrocarbon chains, ring structures
Ions
- Atoms with an electrical charge (anions/cations)
- Examples include: calcium, sodium, magnesium, and phosphate
- Necessary for cellular reactions and processes (e.g., nerve impulses)
Sugars
- Simplest forms are monosaccharides (CH2O)n (n=3, 4, 5, or 6)
- Monosaccharides can link via glycosidic bonds to form larger carbohydrates (e.g. disaccharides & polysaccharides)
- Glucose : important energy source that's broken down to release energy
- Glucose is stored in cells as glycogen (energy storage)
Fatty acids
- Organic molecules with a hydrocarbon chain and a carboxyl group
- Hydrophobic hydrocarbon chain and hydrophilic carboxyl group
- Broken down in mitochondria to produce energy
- Linked to form complex lipid molecules (e.g. triglycerides)
Lipids
- Insoluble in water but soluble in non-polar organic solvents
- Important lipid types are phospholipids and cholesterol (form cell membranes) and triglycerides (energy store)
Phospholipids and cholesterol
- Major components of cellular membranes
Triglycerides
- Made of glycerol and three fatty acids
- Major energy storage form
Amino acids
- Small organic molecules with a carboxyl group & an amino group
- The a-carbon bears distinctive side chains
- Essential for protein synthesis
Proteins
- Polymers of amino acids linked by peptide bonds
- Form polypeptide chains, folded into complex 3D structures for various functions (structural/functional proteins)
Structural proteins
- Form filaments (e.g., actin, intermediate, microtubules)
- Create cytoskeletons for cell structure and movement
- Found in connective tissues (tendons, ligaments)
Functional proteins
- Mostly enzymes, functioning as catalysts for specific reactions
- Accelerate the rate of chemical reactions
- Do not undergo permanent change during reactions
Nucleotides
- 5-carbon sugar linked to a nitrogen-containing base & one or more phosphate group
- The sugars are either ribose or deoxyribose
- Bases include: adenine, thymine, uracil, cytosine, guanine
- Building blocks of nucleic acids
Nucleotides are building blocks of nucleic acids
- Nucleic acids (e.g., DNA and RNA) are linked by phosphodiester bonds
- Involved in storage and retrieval of biological information
Adenosine triphosphate (ATP)
- Molecule that carries energy needed for cellular processes (e.g., muscle contraction, nerve impulses)
- Stores energy in high-energy phosphate bonds
- Release of energy from ATP involves cleavage of phosphate bonds
Small organic molecules
- Are building blocks of macromolecules (sugars, fatty acids, amino acids, nucleotides)
The diversity of cells
- Many cell types in the human body (~200 types)
- Different morphologies and functions
- Different lifespans (e.g., white blood cells ~13 days, red blood cells ~120 days, neurons throughout lifespan)
Prokaryotic and eukaryotic cells
- Prokaryotic cells (e.g., bacteria and archaea) lack a nucleus.
- Eukaryotic cells (e.g., animal and plant cells) possess a nucleus.
- Key difference: presence of a nucleus in eukaryotic cells.
Prokaryotic cell structure
- Small size (0.2-2 µm)
- Lack membrane-enclosed organelles
- Have cell walls
- Have circular DNA located in nucleoid
Prokaryotic cells
- Diverse habitats (Human body ,Ocean floor, volcanic muds)
- Survive using organic (sugars, amino, hydrocarbons, methane) and inorganic (CO2, Fe2+) sources, and light
- Bacteria/Archaea
Bacteria
- Traditionally classified by shape (spherical, rod, spiral)
- Gram-positive/Gram-negative
- Exist for ~3.5 billion years
- Some cause disease, others are beneficial
- ~10¹⁴ microbes in the human body
Eukaryotic cell structure
- Larger size (10-100 µm)
- Contain membrane-enclosed organelles
- No cell wall (only membrane)
- DNA enclosed in the nucleus
- Linear DNA with multiple strands
- Animal cells, plant cells, fungi
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Description
This quiz covers the fundamental concepts of cellular and molecular biology as taught by Dr. Michaeloudes at the European University Cyprus. Focus areas include the structure and functions of cells, differences between prokaryotic and eukaryotic cells, and the importance of cells in living organisms.
