Science Chapter 2: Cells the Building Block of life

Where was Life believed to have Originated from?

It is widely accepted amongst Scientists that life originated in water.

What are heat-loving bacteria known as?

Thermophiles (Unicellular)

Which Mineral Forms Rapidly around Hot springs and protects organic Molecules from Radiation

Calcium Carbonate

Which Place in India has similar springs similar to the Hot Springs where Life first Formed?

the hot springs of Puga Valley in Ladakh

Which group of researchers in Lucknow found out the role of CaCo₃ in the Formation of Life

Scientists from the Birbal Sahni Institute of Palaeosciences

What is a cell?

The Cell is the basic Structural and functional unit of life

What are Tissues?

A group of similar cells performing similar functions form tissues

What are Organs and Organ Systems?

Different tissues are organised to form an organ and several organs work together to form organ systems.

Define Near point.

The distance from which the human eye views objects to see them clearly.

What is the length the Near Point of the Human Eye?

25 cm

Define Limit of Resolution

The ability of the eye to see two very close objects as separate and distinct rather than a single point.

What is the Value of the Limit of Resolution of the human eye?

0.1mm

What are the items used for an Object to be Magnified?

An objective lens and an eyepiece

Who was the First person to observe a cell, Which year was it?

Robert Hooke in 1665

How many Micrometers are in a millimetre?

1mm = 1000 µm

How would You Measure the Estimated size of a cell?

Estimated size of a cell = Diameter of the visible field in microns/ Number of cells along the diameter

What is the Cell membrane? What is also called

The cell membrane is a thin boundary that surrounds a cell and protects its contents, it`s also a plasma membrane

Define Diffusion

Diffusion is the net movement of particles from a higher to a lower concentration

Define Osmosis

The diffusion of water through a selectively permeable membrane is called osmosis

Define Hypertonic, Hypotonic and Isotonic Solution

1. Hypertonic Solution: Intracellular Solute concentration , < Exrtacellular Solute Concentration

2. Hypotonic: Intracellular Solute concentration > Exrtacellular Solute Concentration

3. Isotonic: Intracellular Solute concentration = Exrtacellular Solute Concentration

What is the estimated width of the cell membrane?

7-10 nanometers

How many nanometers is one millimeter?

1mm = 1000000nm

What is this model that explains cell structure called? Why is it called that?

The Fluid Mosaic Model, It`s called that because the molecules can move around freely like a Fluid & the molecules being arranged like tiles in a mosaic

What is a cell wall?

The hard, permeable, outer covering of a cell, that helps maintain a firm structure

Which kinds of cells have cell walls?

The cells of plant, fungi, and bacteria have cell walls

{what is plasmolysis?}

The process of the cell shrinking due to being in a hypertonic solution, but the Cell wall staying intact

What are organelles?

sub-cellular components called organelles

What are the contents present in the cytoplasm

The cytoplasm contains several organelles, along with other substances present in it.

What is a Prokaryote?

a type of cell that lacks a well-defined nucleus and membrane-bound organelles. Eg: Bacteria

What is a Eukaryote?

Cells have a well-defined nucleus and several membrane-bound organelles. Eg: Plant cells, Animal cells

What do the terms "Prokaryote" and "Eukaryote" literally mean?

Prokaryote:

• Pro = Primitive

• Karyon = Nucleus

Eukaryote:

• Eu = True

• Karyon = Nucleus

What is the nucleus?

The nucleus is the double membraned organelle that houses the DNA

What is made in the nucleolus?

The nucleolus makes the ribosomal subunits, The large subunit and the small one

What is the distinct characteristic of the nuclear membrane?

It consists of two layers, often referred to as the nuclear envelope, this envelope is also part of the ER

What do ribosomal subunits assemble to make? what does it do?

ribosomal subunits assemble into ribosomes which use amino acids to make proteins

What is DNA? What is a gene?

DNA or Deoxyribonucleic acid is the master molecule containing the complete set of instructions for running the cell , a Gene is a part of DNA for something specific

What is Chromatin?

Chromatin is a material that looks like an entangled mass of thread-like structures, it is DNA wrapped in Proteins (BONUS: Histone proteins)

What are Chromosomes?

Chromosomes contain information for the transfer of genetic information from parent to offspring

What is a Nucleoid?

The open region in the cytoplasm of a prokaryotic cell where its genetic material (DNA) is concentrated.

what are the sites of protein synthesis?

Ribosomes

What is the Endoplasmic Reticulum?

A large, network-like organelle physically attached to the nucleus, serving as the cell's main manufacturing and transport hub.

What are the functions of the RER?

• Protein Synthesis: Is the place where the ribosomes make proteins

• Protein Processing: Customises the simple protein chains into 3D Shapes

• Protein Secretion: Packages Proteins and protein made compounds into vesicles

What are the functions of the SER?

• Lipid Synthesis: Makes Lipid molecules and {Steroid proteins}

• Detoxification: Contains specialised Enzymes to break down and flush out toxins

Who first observed the Golgi Apparatus in a cell?

Camillo Golgi in 1898

What is the Golgi apparatus?

A system of separate, membrane-bound, flattened sacs {cisternae} stacked parallel to each other that serves as the cell's packaging and dispatch facility.

How is the Golgi linked to the Endoplasmic reticulum?

They are Functionally linked because vesicles from the ER need to go to the Golgi apparatus for modification, and finally trasportation to the entire cell

What are vesicles?

These are membrane bound sacs usually used for transporting proteins from the RER to the Golgi

What are Lysomes?

Lysosomes are single membrane-bound sacs filled with enzymes, which can break down unwanted compounds and damaged parts of a cell.Lysomes are vesicles just filled with enzymes.

Where are Lysomes made?

Lysomes are made in the Golgi Apparatus.

What are Mitochondria? what are they commonly referred to as?

Mitochondria generate energy for the cell by using glucose to produce ATP, hey are commonly known as, “the powerhouse of the cell”

What are Cristae? what molecules sit in them?

Cristae are the folds of the inner membrane of the mitochondria, ATP Synthase sit in them

What is ATP?

ATP (Adenosine Triphosphate) is the energy currency used in cells, it is made by the ATP Synthase molecules in the mitochondria

What are Plastids?

Plastids are double membraned organelles found only in plant and algae cells that store pigment or starch and oil

What are the two typesof Plastids?

Chromoplasts: these store pigments to attract pollinators

Leucoplasts: these store starch and oils

What do “Chromoplasts” and “Leucoplasts” literally mean?

In greek:

Chroma = colour

Leuco = white

What do Chromoplasts and leucoplasts do? what about Chloroplasts?

Chromoplasts store colour, this is to attract pollinators and seed dispersers

Chloroplasts, a type of chromoplast with chlorophyll, it turns sunlight into glucose

Leucoplasts store starch or fat, this is incase there is no sunlight for the chloroplasts to make glucose