Biomolecules in Reductionist Biology Chapter 9

Questions and Answers

What occupies the volume of both prokaryotic and eukaryotic cells?

Ribosomes

Nucleus

Organelles

Cytoplasm (correct)

Which of the following is a membrane-bound organelle found in eukaryotic cells?

Ribosome

Chloroplast (correct)

Mitochondria (correct)

Centrosome

Which organelle helps in cell division in animal cells?

Golgi complex

Cytoplasm

Centrosome (correct)

Mitochondria

What distinguishes prokaryotic cells from eukaryotic cells regarding organelles?

Prokaryotic cells lack membrane-bound organelles. Signup and view all the answers

Where are ribosomes typically found within a eukaryotic cell?

In the cytoplasm and on rough ER Signup and view all the answers

What is the main focus of Reductionist Biology?

Applying physics and chemistry to study biology Signup and view all the answers

What notable structure did G.N. Ramachandran discover?

Triple helical structure of collagen Signup and view all the answers

Which of the following techniques is associated with G.N. Ramachandran?

The development of the Ramachandran plot Signup and view all the answers

Where did G.N. Ramachandran complete his Ph.D.?

Cambridge University Signup and view all the answers

On which date was G.N. Ramachandran born?

October 8, 1922 Signup and view all the answers

Which figure influenced Ramachandran during his time at Cambridge?

Linus Pauling Signup and view all the answers

What did Ramachandran study in relation to biopolymers?

Allowed conformations of proteins Signup and view all the answers

At what age did G.N. Ramachandran pass away?

78 Signup and view all the answers

What role does the quasi-fluid nature of lipids play in the plasma membrane?

It enables the lateral movement of proteins within the bilayer. Signup and view all the answers

Which transport mechanism does not require energy?

Simple diffusion of neutral solutes along the concentration gradient. Signup and view all the answers

What is the process called when water moves across a membrane from higher to lower concentration?

Osmosis. Signup and view all the answers

Which statement correctly describes active transport?

It moves ions or molecules against their concentration gradient using ATP. Signup and view all the answers

What is one of the primary functions of the plasma membrane?

Facilitating transport of molecules across the membrane. Signup and view all the answers

What helps polar molecules to pass through the nonpolar lipid bilayer of the membrane?

Carrier proteins. Signup and view all the answers

Which feature characterizes cell walls in fungi and plants?

They provide mechanical stability and protection. Signup and view all the answers

What is a primary role of the fluid nature of the plasma membrane in cellular functions?

Enabling processes like cell growth and secretion. Signup and view all the answers

What is the primary function of cilia in cells?

To cause movement of the cell or surrounding fluid Signup and view all the answers

What structural arrangement do the microtubules in the axoneme of cilia and flagella exhibit?

9+2 array Signup and view all the answers

What distinguishes prokaryotic flagella from eukaryotic flagella?

Prokaryotic flagella have a different structural composition Signup and view all the answers

How are the central tubules connected in the axoneme?

By radial spokes Signup and view all the answers

What is the role of the basal bodies in relation to cilia and flagella?

To anchor the cilia and flagella to the cell membrane Signup and view all the answers

What type of arrangement do centrioles have within a centrosome?

Perpendicular arrangement Signup and view all the answers

What component links the triplet peripheral fibrils in centrioles?

Linking proteins Signup and view all the answers

What is the composition of the hub located in the proximal region of each centriole?

A proteinaceous structure Signup and view all the answers

What are the roles of centrioles in animal cells?

Formation of cilia or flagella Signup and view all the answers

Who first described the nucleus as a cell organelle?

Robert Brown Signup and view all the answers

What is chromatin composed of?

Nucleic acids and proteins Signup and view all the answers

What does the nuclear envelope do?

It separates the nucleus from the cytoplasm Signup and view all the answers

What is the function of nucleoli within the nucleus?

Ribosome production Signup and view all the answers

What is the perinuclear space?

The space between the two membranes of the nuclear envelope Signup and view all the answers

What keeps the outer membrane of the nuclear envelope continuous?

Endoplasmic reticulum Signup and view all the answers

Which component does NOT belong to the structure of the nucleus?

Centrioles Signup and view all the answers

Study Notes

Reductionist Biology

A physico-chemical approach used to study and understand living organisms through concepts and techniques from physics and chemistry.
Biomolecules are briefly described in Chapter 9 of the referenced unit.

G.N. Ramachandran

Founder of the 'Madras school' of conformational analysis of biopolymers.
Known for discovering the triple helical structure of collagen in 1954; published findings in Nature.
Developed the 'Ramachandran plot' for analyzing allowed protein conformations.
Born on October 8, 1922, near Cochin, India; significant early influence from his father, a mathematics professor.
Graduated top of his class in B.Sc. (Honors) Physics from the University of Madras in 1942.
Earned a Ph.D. from Cambridge University in 1949; influenced by Linus Pauling's work on protein structures.
Passed away on April 7, 2001, at the age of 78.

Cytoplasm and Cell Structure

Cytoplasm is a semi-fluid matrix occupying cell volume in prokaryotic and eukaryotic cells, serving as the main site for cellular activities.
Eukaryotic cells contain organelles (e.g., endoplasmic reticulum, Golgi complex, lysosomes, mitochondria) which are not found in prokaryotic cells.
Ribosomes, non-membrane bound organelles, are present in all cells, located in the cytoplasm, chloroplasts (plants), mitochondria, and rough ER.
Animal cells additionally possess centrosomes, which assist in cell division.

Plasma Membrane Dynamics

The fluid nature of the plasma membrane enables protein movement, crucial for functions like growth, secretion, and cell division.
Plasma membranes are selectively permeable, allowing some molecules to traverse without energy (passive transport).
Neutral solutes and water pass through the membrane via simple diffusion and osmosis, respectively.
Polar molecules require carrier proteins for transport across the lipid bilayer.
Active transport involves moving ions or molecules against their concentration gradient using ATP, like the Na+/K+ pump.

Cell Wall and Locomotion Structures

The cell wall provides a rigid outer covering for plant and fungal cells, offering shape, protection, and facilitating cell-to-cell interactions.
Cilia and flagella enable cell movement; cilia are short and oar-like, flagella are long and whip-like.
Prokaryotic and eukaryotic flagella differ structurally, both covered by plasma membrane with an axoneme structure (9+2 arrangement of microtubules).

Centrosome and Centrioles

The centrosome contains two centrioles arranged perpendicularly, each made up of nine peripheral triplets of tubulin.
Centrioles are involved in forming the basal body of cilia/flagella and spindle fibers during cell division.

Nucleus Structure

Robert Brown first described the nucleus in 1831; chromatin (nuclear material) was later identified by Flemming.
Interphase nucleus features nucleoprotein fibers (chromatin), nucleoplasm, and nucleoli.
The nuclear envelope comprises two membranes, creating a perinuclear space (10 to 50 nm) that separates nuclear content from cytoplasm, and is continuous with the endoplasmic reticulum.

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Explore the concepts of Reductionist Biology through Chapter 9, focusing on the physico-chemical principles applied to understand living organisms. Gain insights into biomolecules and the contributions of G.N. Ramachandran in protein structure. This quiz will enhance your grasp of how physics and chemistry intersect with biology.