Week 1 Biology Chapter on Macromolecules

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Questions and Answers

What are macromolecules primarily composed of?

Fatty acids

Inorganic compounds

Water-soluble organic molecules (correct)

Vitamins

Which of the following is NOT a type of macromolecule found in cells?

Minerals (correct)

Enzymes

Nucleic acids

Proteins

What is the primary function of molecular self-assembly?

To spontaneously form complex structures from macromolecules (correct)

To degrade macromolecules into monomers

To synthesize new organic molecules

To stabilize cellular membranes

Which type of self-assembly requires external assistance from molecular chaperones?

Assisted self-assembly Signup and view all the answers

What are the building blocks that polymerize to form macromolecules called?

Monomers Signup and view all the answers

What type of structure is formed when macromolecules assemble into larger organized aggregates?

Supramolecular structures Signup and view all the answers

What is a critical feature of the native conformation of proteins?

It minimizes energy states Signup and view all the answers

Which of the following best describes macromolecules?

They may exist as single molecules or organize into larger structures. Signup and view all the answers

What is the primary function of the phospholipid bilayer in cells?

To maintain homeostasis in the internal environment Signup and view all the answers

Which type of molecules can easily pass through the cell membrane?

Small hydrophobic molecules Signup and view all the answers

What term describes the ability of the cell membrane to allow certain substances to enter or exit while blocking others?

Selective permeability Signup and view all the answers

Which type of membrane proteins extend across the bilayer and interact with both the internal and external environments of the cell?

Transmembrane proteins Signup and view all the answers

Where are peripheral membrane proteins located?

On the outside surfaces of membranes Signup and view all the answers

What characteristic of hydrophilic molecules affects their ability to cross the cell membrane?

Size and charge of the molecules Signup and view all the answers

What distinguishes integral membrane proteins from peripheral membrane proteins?

Integral proteins extend across the membrane Signup and view all the answers

What role do membrane proteins play in relation to substances entering or exiting the cell?

They facilitate transport and signaling. Signup and view all the answers

What topic is covered during Week 3 of the course?

Cells and organelles Signup and view all the answers

During which week is the mid-term test scheduled?

Week 7 Signup and view all the answers

Which topic is introduced in Week 10 of the course?

The cell cycle, DNA replication and mitosis Signup and view all the answers

What is the primary focus of Week 12's topic?

Cancer cells Signup and view all the answers

Which seminar session is scheduled for early Friday mornings?

Seminar session 2 Signup and view all the answers

What aspect of cell biology is discussed in Week 4?

Discovery of cells and microscopy Signup and view all the answers

What significant event occurs during Week 14?

Revision session for the course Signup and view all the answers

Which topic concerning genetics is included in Week 11?

Sexual reproduction, mitosis, meiosis and genetic recombination Signup and view all the answers

What is covered during Week 1 of the course?

Course introduction and a preview of the cell Signup and view all the answers

What is the main focus of Week 8's lecture?

Signal transduction mechanism I Signup and view all the answers

What percentage of the total assessment is attributed to the final examination?

40% Signup and view all the answers

Who first observed cell division during the formation of pollens?

Carl Nägeli Signup and view all the answers

How many assignments are listed in the assessment structure?

Two Signup and view all the answers

Which function is NOT attributed to cells?

Transport information Signup and view all the answers

What is the role of specialized cells once they develop?

Respond to stimuli and adapt Signup and view all the answers

What is the total weight of the project in the overall assessment?

30% Signup and view all the answers

What is a common characteristic of all cells?

They can reproduce Signup and view all the answers

Which of the following describes unicellular organisms?

Consist of a single cell Signup and view all the answers

When is the mid-term test scheduled?

Week 7 Signup and view all the answers

Which of the following is NOT a function of cells?

Facilitate communication between organisms Signup and view all the answers

What is the primary reason why water is considered the universal solvent in biological systems?

Its polarity enables it to dissolve a variety of solutes. Signup and view all the answers

What percentage of a cell's weight is typically attributed to water?

75–85% Signup and view all the answers

What is the shape of a water molecule in terms of its atomic arrangement?

Bent Signup and view all the answers

What type of bond forms between water molecules due to their polar nature?

Hydrogen bonds Signup and view all the answers

Why does water have a high surface tension?

Because of cohesive forces between water molecules. Signup and view all the answers

What is adhesion in the context of water molecules?

Water molecules sticking to other substances. Signup and view all the answers

Which type of molecules readily dissolve in water?

Hydrophilic molecules Signup and view all the answers

What distinguishes hydrophobic substances from hydrophilic substances?

Hydrophobic substances do not interact with water. Signup and view all the answers

What does the term 'half-life' refer to in the context of hydrogen bonds in water?

Duration for hydrogen bonds to break and reform. Signup and view all the answers

What contributes to the polarity of the water molecule?

The unequal distribution of electrons within the molecule. Signup and view all the answers

Which characteristic of water allows some insects to walk on its surface?

Surface tension due to cohesion. Signup and view all the answers

What happens to NaCl when it dissolves in water?

The solvent molecules overcome the attraction between Na+ and Cl- ions. Signup and view all the answers

What is the typical bond angle between the hydrogen atoms in a water molecule?

104.5° Signup and view all the answers

What is the significance of the tetravalent nature of the carbon atom in organic chemistry?

The tetravalent nature of carbon allows it to form four covalent bonds, leading to diverse and complex carbon-containing molecules. Signup and view all the answers

How does the bond energy of carbon-carbon (C−C) bonds compare to other carbon-containing bonds?

The bond energy of carbon-carbon (C−C) bonds is 83 kcal/mol, which is similar to the bond energies of carbon-nitrogen (C−N) and carbon-oxygen (C−O) bonds. Signup and view all the answers

Explain the role of functional groups in carbon-containing molecules.

Functional groups impart specific chemical properties to carbon-containing molecules, influencing their reactivity and interactions. Signup and view all the answers

Why is carbon often referred to as the backbone of biological molecules?

Carbon serves as the backbone for biological molecules because it can form long chains and rings that are essential for complex structures. Signup and view all the answers

What is the octet rule and how does it relate to the stability of carbon compounds?

The octet rule states that atoms are most stable when surrounded by eight electrons; carbon, which has four outer electrons, seeks to fulfill this by forming four bonds. Signup and view all the answers

What are the two types of molecular self-assembly and how do they differ?

The two types are strict self-assembly, which occurs without any external factors, and assisted self-assembly, which requires molecular chaperones for correct folding. Signup and view all the answers

Explain the role of monomers in the synthesis of macromolecules.

Monomers polymerize to form macromolecules, which can function independently or combine into supramolecular structures. Signup and view all the answers

What is the significance of the native conformation of proteins?

The native conformation is critical for a protein's functionality, as it determines how the protein interacts with other molecules. Signup and view all the answers

Why are macromolecules essential to cellular structures?

Macromolecules, formed by polymerization of small molecules, create ordered arrays that make up the structural components of cells. Signup and view all the answers

How do supramolecular structures contribute to cellular organization?

Supramolecular structures are formed by the assembly of macromolecules, which play key roles in organizing organelles and other cellular components. Signup and view all the answers

What is the size range of bacterial cells in micrometers?

Bacterial cells are a few micrometers (µm) in diameter. Signup and view all the answers

What is the primary role of cells in living organisms?

Cells provide structure, support, and facilitate essential functions such as growth and energy production. Signup and view all the answers

What significant contribution did Robert Hooke make to cell biology in 1665?

Robert Hooke built a microscope and discovered cells in cork, calling them 'cells'. Signup and view all the answers

Describe one key difference between multicellular and unicellular organisms.

Multicellular organisms are composed of many cells, while unicellular organisms consist of a single cell. Signup and view all the answers

Why are most cells invisible to the naked eye?

Most cells are too small and require a microscope to be seen. Signup and view all the answers

What role does water play in cell biology?

Water is crucial as it acts as a universal solvent and is involved in biochemical reactions. Signup and view all the answers

How do specialized cells respond to environmental changes?

Specialized cells have the capability to respond to stimuli and adapt to changes in their environment, enhancing their functionality. Signup and view all the answers

What process allows cells to grow and reproduce?

Cells grow and reproduce primarily through a process called mitosis. Signup and view all the answers

How does the size of animal and plant cells compare to bacterial cells?

Animal and plant cells are typically 10-20 times larger than bacterial cells. Signup and view all the answers

What is polymerization in the context of cell biology?

Polymerization is the process of small molecules joining together to form larger macromolecules. Signup and view all the answers

Who first observed cell division and in what context?

Carl Nägeli first observed cell division during the formation of pollens. Signup and view all the answers

What is one critical function of cells related to metabolism?

Cells create metabolic reactions which are vital for maintaining life processes. Signup and view all the answers

What is the significance of carbon in cellular structures?

Carbon is essential as it forms the backbone of macromolecules like proteins, lipids, carbohydrates, and nucleic acids. Signup and view all the answers

In what way do cells transport substances across their membranes?

Cells engage in both passive and active transport to regulate the movement of substances across their membranes. Signup and view all the answers

How do selectively permeable membranes benefit cells?

They allow cells to control the movement of substances in and out, maintaining homeostasis. Signup and view all the answers

What does the term 'cells' mean in Latin, and how is it relevant to cell biology?

'Cells' means 'little rooms' in Latin, reflecting the structures observed in biological samples. Signup and view all the answers

What aspect of cellular chemistry does self-assembly refer to?

Self-assembly refers to the process by which molecules organize into structured arrangements spontaneously. Signup and view all the answers

Study Notes

Cellular Hierarchy

Most cellular structures are composed of small, water-soluble organic molecules.
These small organic molecules, or monomers, polymerize to form macromolecules.
These macromolecules can function independently or be assembled into supramolecular structures.
Supramolecular structures are components of organelles and other subcellular structures, ultimately making up the cell itself.

Self-Assembly

Molecular self-assembly is the spontaneous folding of macromolecules and their interaction to form more complex structures.
This process is inherent in the polymers themselves, such as the native conformation of a protein.
Two types of self-assembly exist:
- Strict self-assembly: Only the polypeptide sequence is required.
- Assisted self-assembly: Requires a specific molecular chaperone to ensure the correct conformation.

Carbon's Importance

Carbon is the most crucial atom in biological molecules, forming the backbone of most compounds important to cell biology.
Carbon forms four chemical bonds with other atoms, satisfying the octet rule by sharing electron pairs in covalent bonds.
Life on Earth would not be possible without carbon, as it is the basis for millions of organic compounds.

Carbon Bonding and Stability

The stability of organic molecules is expressed as bond energy, a measure of the energy required to break a bond.
Bond energies are typically expressed in calories per mole (cal/mol).
Covalent bonds are strong and require a significant amount of energy to break, which contributes to the stability of organic molecules.

Carbon-Containing Molecules

The diversity of carbon-containing molecules is a result of the tetravalent nature of the carbon atom.
Hydrocarbons, consisting of only carbon and hydrogen atoms, are relatively insoluble in water.
Functional groups are specific arrangements of atoms that confer distinct chemical properties on the molecules they are attached to.

Water's Importance

Water is the most abundant component of cells and organisms, playing a vital role as the universal solvent in biological systems.
The polarity of water molecules, caused by the unequal distribution of electrons, is its most critical attribute.
The bent shape of the water molecule, with its partial negative charge on the oxygen atom and partial positive charges on the hydrogen atoms, allows for hydrogen bonding.

Properties of Water

Water molecules are highly cohesive due to the formation of hydrogen bonds between adjacent molecules.
This cohesiveness accounts for water's high surface tension and its role as an excellent solvent.
Water's adhesive properties allow it to move upwards through plant tissues and enable insects to move across water's surface.

Water as a Solvent

Water's polarity allows it to effectively dissolve a wide range of solutes, making it an excellent solvent for biological systems.
Hydrophilic molecules, with an affinity for water, dissolve readily, while hydrophobic molecules, lacking this affinity, do not.
Some biological macromolecules have both hydrophilic and hydrophobic regions, making them amphipathic.

Polymerization of Small Molecules

Most cellular structures are made of ordered arrays of linear polymers called macromolecules.
Important macromolecules in the cell include proteins, nucleic acids (DNA and RNA), polysaccharides, and lipids.
These macromolecules are synthesized by the polymerization of small molecules.
This process involves joining monomers together, forming a chain-like structure.

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Test your knowledge on macromolecules with this quiz. Answer questions about their composition, types, functions, and the process of molecular self-assembly. Perfect for students studying cellular biology.