Quick Review Flashcards - Click to flip and test your knowledge!
Question
Why was the curved glass used to enlarge small objects named a 'lens'?
Answer
It was shaped like a lentil seed (thick in the middle and thin at the edge).
Question
In what year did the scientist Robert Hooke publish his findings in the book *Micrographia*?
Answer
$1665$
Question
What material was Robert Hooke observing under the microscope when he discovered 'cells'?
Answer
A thin slice of cork.
Question
Why did Robert Hooke choose the word 'cell' to describe the structures he saw in cork?
Answer
The compartments reminded him of the small spaces in a honeycomb.
Question
According to the text, who is known as the 'Father of Microbiology'?
Answer
Antonie van Leeuwenhoek.
Question
Which Dutch scientist was the first to clearly see and describe bacteria and blood cells in the $1660$s?
Answer
Antonie van Leeuwenhoek.
Question
What is the basic biological unit of all living organisms?
Answer
The cell.
Question
Which red-coloured stain is used in Activity $2.2$ to make onion peel cells visible?
Answer
Safranin.
Question
In microscope slide preparation, what is the purpose of adding a drop of glycerin to the specimen?
Answer
It prevents the cells from drying out and improves visual clarity.
Question
What is the characteristic shape of the cells observed in an onion peel?
Answer
Nearly rectangular.
Question
Which blue-coloured stain is used in Activity $2.3$ to observe human cheek cells?
Answer
Methylene blue.
Question
What is the characteristic shape of human cheek cells?
Answer
Polygon-shaped.
Question
What are the three basic parts found in most cells?
Answer
Cell membrane, cytoplasm, and nucleus.
Question
What is the function of the cell membrane's porous structure?
Answer
It allows essential materials to enter and waste materials to exit the cell.
Question
What is the function of the cell nucleus?
Answer
It regulates all activities within the cell and controls growth.
Question
Where do most of the life processes take place within a cell?
Answer
In the cytoplasm.
Question
Which extra outer layer is found in plant cells but absent in animal cells?
Answer
The cell wall.
Question
What is the primary function of the cell wall in plants?
Answer
It provides rigidity and strength.
Question
What are plastids?
Answer
Tiny rod-shaped structures found in all parts of a plant.
Question
Which specific plastids contain chlorophyll and aid in photosynthesis?
Answer
Chloroplasts.
Question
How does the size of the vacuole typically differ between plant and animal cells?
Answer
Plant cells have a large vacuole, while animal cells have very small or no vacuoles.
Question
What is the typical shape of a human muscle cell?
Answer
Spindle-shaped.
Question
What physical characteristic of a nerve cell allows it to pass messages quickly through the body?
Answer
Its long and branched structure.
Question
List the levels of biological organisation from the cell to the complete organism.
Answer
Cell $\rightarrow$ Tissue $\rightarrow$ Organ $\rightarrow$ Organ system $\rightarrow$ Organism.
Question
What is the definition of a multicellular organism?
Answer
A living being made up of many cells.
Question
What is the largest known single cell in the living world?
Answer
The yolk of an ostrich egg.
Question
What is the approximate diameter range of the yolk of an ostrich egg?
Answer
$130$ mm to $170$ mm.
Question
Term: Microorganisms (Microbes)
Answer
Living beings so small that they cannot be seen with the naked eye.
Question
Which two examples of microorganisms are cited as being made of just one cell (unicellular)?
Answer
Bacteria and *Amoeba*.
Question
What is a 'foldscope'?
Answer
A low-cost and foldable paper microscope.
Question
To which group of microorganisms do *Amoeba* and *Paramecium* belong?
Answer
Protozoa.
Question
What are the four main categories of microorganisms identified in Grade $8$ activities?
Answer
Protozoa, algae, fungi, and bacteria.
Question
Which microorganisms are described as 'microscopic and acellular'?
Answer
Viruses.
Question
Under what specific condition do viruses multiply?
Answer
When they enter a living cell.
Question
How do microorganisms like fungi and bacteria benefit the environment?
Answer
They act as decomposers, breaking down waste into nutrient-rich manure.
Question
In ancient Indian texts, what does the word 'Krimi' refer to?
Answer
Different tiny entities, including visible ('Drishya') and invisible ('Adrishya') ones.
Question
Which specific Vedic text contains references to 'Krimi'?
Answer
The *Atharvaveda*.
Question
What is the primary gas found in the fuel source known as biogas?
Answer
Methane.
Question
Which scientist developed a bacterium in $1971$ specifically to break down oil spills?
Answer
Dr. Ananda Mohan Chakrabarty.
Question
Term: Patent
Answer
A copyright given to an inventor so no one else can copy, use, or sell the invention without permission.
Question
To which group of microorganisms does yeast belong?
Answer
Fungi.
Question
What gas is released by yeast during respiration, causing dough to rise?
Answer
Carbon dioxide ($CO_2$).
Question
What byproduct produced by yeast gives dough a slightly different smell?
Answer
Alcohol.
Question
Which bacterium is essential for the fermentation of batter used for making idli and dosa?
Answer
Lactobacillus.
Question
Why do high concentrations of salt or sugar in pickles and murabbas prevent food spoilage?
Answer
They act as preservatives that do not allow microorganisms to grow.
Question
The process where microorganisms breakdown plant waste into manure occurs best at _____.
Answer
Optimal temperature and appropriate moisture levels.
Question
What are the common structural shapes of bacteria?
Answer
Spherical, rod-shaped, comma, or spiral.
Question
Which microorganism is described as a branched filament without chlorophyll having a brush-like structure?
Answer
Mould (Penicillium).
Question
What is the role of muscle cells in the human stomach wall?
Answer
They help churn the food during digestion.
Question
Which type of human cell is thin and flat to form a protective inner lining of the mouth?
Answer
Cheek cells.