G.N. Ramachandran and Cellular Concepts

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What significant structure did Ramachandran discover in 1954?

Triple helical structure of collagen (correct)

Alpha-helix structure of proteins

Beta-sheet structure of proteins

Double helical structure of DNA

Which influential figure did Ramachandran meet during his time at Cambridge?

Richard Feynman

James Watson

Linus Pauling (correct)

Francis Crick

What educational achievement did Ramachandran complete first?

Ph.D. from Cambridge University

Graduation in B.Sc. (Honors) Physics (correct)

Postdoctoral research

High school diploma

What is one of Ramachandran's notable contributions to structural biology?

Development of the Ramachandran plot Signup and view all the answers

In which year did Ramachandran receive his Ph.D.?

1949 Signup and view all the answers

Which academic institution had a significant influence on Ramachandran's education due to his father's role?

University of Madras Signup and view all the answers

What distinguishes unicellular organisms from non-cellular structures?

They can live independently. Signup and view all the answers

Where was Ramachandran born?

Cochin Signup and view all the answers

At what age did Ramachandran pass away?

78 Signup and view all the answers

What was the significant contribution of Rudolf Virchow to cell theory?

He proposed that new cells arise from pre-existing cells. Signup and view all the answers

Which part of the cell is unique to plant cells as noted by Theodore Schwann?

Cell wall Signup and view all the answers

Who first described live cells using a microscope?

Anton Von Leeuwenhoek Signup and view all the answers

What did Matthias Schleiden's observations lead him to conclude about plants?

Plants are composed of different types of cells. Signup and view all the answers

Which statement accurately reflects the cell theory as formulated by Schleiden and Schwann?

All living organisms are composed of cells and cell products. Signup and view all the answers

Which of the following advancements allowed for better observation of cell structures?

Electron microscopes Signup and view all the answers

What is the primary role of the plasma membrane in cells?

To control the movement of substances in and out of the cell. Signup and view all the answers

What type of transport allows molecules to move across the membrane without energy?

Passive transport Signup and view all the answers

In which process does water move from higher to lower concentration?

Osmosis Signup and view all the answers

Which type of molecules require a carrier protein to facilitate their transport across the plasma membrane?

Polar molecules Signup and view all the answers

What type of transport moves ions against their concentration gradient?

Active transport Signup and view all the answers

What is the composition of the primary cell wall in plants?

Cellulose, hemicellulose, pectins, and proteins Signup and view all the answers

What layer mainly holds neighboring plant cells together?

Middle lamella Signup and view all the answers

Which of the following is NOT a function of the cell wall?

Facilitates transport across the membrane Signup and view all the answers

What is the purpose of plasmodesmata in plant cells?

To connect the cytoplasm of neighboring cells Signup and view all the answers

What do amyloplasts primarily store?

Carbohydrates Signup and view all the answers

Which structure in chloroplasts is responsible for carrying out photosynthesis?

Thylakoids Signup and view all the answers

What is the primary function of leucooplasts?

Storage of nutrients Signup and view all the answers

How many chloroplasts can typically be found in the mesophyll cells?

20-40 Signup and view all the answers

What is the space limited by the inner membrane of the chloroplast called?

Stroma Signup and view all the answers

Which type of leucoplast stores oils and fats?

Elaioplasts Signup and view all the answers

What connects the thylakoids of different grana?

Stroma lamellae Signup and view all the answers

Which of the following statements about chloroplasts is incorrect?

Chloroplasts have a single membrane. Signup and view all the answers

What distinguishes cilia from flagella in terms of structure and function?

Cilia are shorter and can either move the cell or the surrounding fluid. Signup and view all the answers

What is the term used to describe the arrangement of microtubules in the axoneme of cilia and flagella?

9+2 array Signup and view all the answers

What connects the central microtubules in the axoneme?

Radial spokes Signup and view all the answers

Which of the following statements is true regarding the structural differences between prokaryotic and eukaryotic flagella?

Prokaryotic flagella are structurally different from eukaryotic flagella. Signup and view all the answers

What role do linkers serve in the structure of cilia and flagella?

They interconnect the peripheral doublets of microtubules. Signup and view all the answers

What is the composition of the axoneme in cilia and flagella?

A core of nine peripheral doublets and two central microtubules Signup and view all the answers

From where do cilia and flagella emerge?

A centriole-like structure known as basal bodies Signup and view all the answers

What characteristic of cilia allows them to create movement in the surrounding fluid?

The way they beat in coordinated patterns. Signup and view all the answers

Study Notes

G.N. Ramachandran

Renowned for contributions to protein structure and conformational analysis of biopolymers.
Founded the ‘Madras school’ of structural biology.
Discovered the triple helical structure of collagen; published in Nature in 1954.
Developed the 'Ramachandran plot' for analyzing protein conformations.
Born on October 8, 1922, near Cochin, India; influenced by a mathematically inclined father.
Graduated in 1942 as top student in B.Sc. (Honors) Physics from the University of Madras.
Earned a Ph.D. from Cambridge University in 1949.
Influenced by Linus Pauling's work on α-helices and β-sheets during his time at Cambridge.
Passed away on April 7, 2001, at age 78.

Understanding Cells

Cells are the basic structural and functional units of all living organisms.
Organisms can be unicellular (single cell) or multicellular (many cells).
Independent living is dependent on the complete structure of a cell; incomplete structures do not suffice.

Cell Theory

Developed by Matthias Schleiden (1838) and Theodore Schwann (1839), who observed that all plants and animals are composed of cells.
Schwann noted the presence of a thin outer membrane (plasma membrane) in cells.
Rudolf Virchow (1855) contributed to cell theory by stating that all cells arise from pre-existing cells (Omnis cellula-e cellula).
Modern cell theory encompasses two main principles:
- All living organisms are composed of cells and products of cells.
- All cells arise from pre-existing cells.

Structure of Plant Cells

Plant cells, like those in onions, have distinct structures including a cell wall and plasma membrane.
Cell membrane is selectively permeable, facilitating passive and active transport of molecules.

Transport Mechanisms

Passive transport allows molecules to move across the membrane without energy, following concentration gradients.
Osmosis refers specifically to water movement across the membrane.
Active transport requires ATP and moves substances against their concentration gradient (e.g., Na+/K+ Pump).

Cell Wall

A rigid structure surrounding the plasma membrane in plants and fungi.
Provides shape, protection, and facilitates intercellular interactions.
Composed of cellulose and other materials that vary by organism (e.g., algae have walls made of calcium carbonate).

Leucoplasts and Chloroplasts

Leucoplasts are colorless plastids that store nutrients; amyloplasts store starch, elaioplasts store oils, and aleuroplasts store proteins.
Chloroplasts are found in mesophyll cells of leaves, essential for photosynthesis and possessing chlorophyll.
Chloroplast structure includes:
- Double membranes with less permeable inner membranes.
- Stroma containing enzymes, DNA, and ribosomes.
- Thylakoids arranged in stacks (grana) where carbohydrate synthesis occurs.

Cilia and Flagella

Hair-like structures that facilitate movement; cilia are shorter and help move fluids, while flagella are longer and propel cells.
Both structures have a core called axoneme, structured in a 9+2 microtubule array.
Emerges from a centriole-like structure (basal body) that anchors them in the cell.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Explore the groundbreaking contributions of G.N. Ramachandran to protein structure and the fundamental understanding of cells as the building blocks of life. This quiz covers his discoveries, including the Ramachandran plot and the nature of unicellular and multicellular organisms. Test your knowledge on these critical topics in biology and biochemistry.