Fundamental Unit of Life

Question 1

Who discovered the cell and how?

Answer 1

Robert Hooke in 1665, using a self-made microscope while observing cork slices.

Question 2

What did Robert Hooke name the tiny boxes he observed?

Answer 2

Cells, which means “a little room” in Latin.

Question 3

What is a unicellular organism?

Answer 3

An organism made up of only one cell, e.g., Amoeba, Chlamydomonas.

Question 4

What is a multicellular organism?

Answer 4

An organism made up of many cells performing different functions.

Question 5

What does the onion peel microscope activity teach us?

Answer 5

It helps observe onion peel cells under a microscope and understand basic cell structure.

Question 6

What does the temporary mount of an onion peel show?

Answer 6

Rectangular cells with a cell wall, cytoplasm, and possibly a nucleus.

Question 7

What was Leeuwenhoek’s contribution?

Answer 7

Discovered free-living cells in pond water using an improved microscope (1674).

Question 8

Who coined the term ‘protoplasm’?

Answer 8

Purkinje in 1839.

Question 9

What is the cell theory and who proposed it?

Answer 9

Schleiden and Schwann proposed that all organisms are made of cells, and Virchow added that all cells come from pre-existing cells.

Question 10

What tool allowed us to see cell organelles in detail?

Answer 10

The electron microscope, invented in 1940.

Question 11

What is the function of the plasma membrane?

Answer 11

It allows selective movement of substances in and out of the cell.

Question 12

Define diffusion.

Answer 12

Movement of molecules from a region of higher concentration to lower concentration.

Question 13

What is osmosis?

Answer 13

Diffusion of water across a selectively permeable membrane.

Question 14

What happens to a cell in a hypotonic solution?

Answer 14

It swells as water enters the cell.

Question 15

What happens in a hypertonic solution?

Answer 15

The cell shrinks due to water loss.

Question 16

What does the egg-in-water/salt solution activity demonstrate?

Answer 16

Osmosis using a de-shelled egg in water and salt solution.

Question 17

What is endocytosis?

Answer 17

Process by which cells engulf materials from the external environment.

Question 18

Why is the plasma membrane called selectively permeable?

Answer 18

It allows only certain substances to pass through.

Question 19

What is the cell wall made of?

Answer 19

Cellulose.

Question 20

What is the function of the cell wall?

Answer 20

Provides structural strength and prevents bursting in hypotonic solutions.

Question 21

What is plasmolysis?

Answer 21

Shrinkage of the cell contents due to water loss.

Question 22

What does the Rhoeo leaf activity show?

Answer 22

Living cells show plasmolysis when placed in strong solutions; dead cells do not.

Question 23

What does the nucleus contain?

Answer 23

Chromatin, nucleoplasm, and nucleolus.

Question 24

What are chromosomes made of?

Answer 24

DNA and proteins.

Question 25

What are genes?

Answer 25

Functional segments of DNA.

Question 26

What is a nucleoid?

Answer 26

An undefined nuclear region in prokaryotes.

Question 27

What are prokaryotes?

Answer 27

Organisms with no nuclear membrane or membrane-bound organelles.

Question 28

What are eukaryotes?

Answer 28

Organisms with a defined nucleus and organelles.

Question 29

What does the cheek cell scraping activity show?

Answer 29

Human cheek cells with visible nucleus when stained with methylene blue.

Question 30

What is cytoplasm?

Answer 30

The fluid content of the cell enclosed by the plasma membrane.

Question 31

What are membrane-bound cell organelles?

Answer 31

Specialized structures in eukaryotic cells like mitochondria, ER, Golgi, etc.

Question 32

Why do viruses not show characteristics of life outside a body?

Answer 32

They lack membranes and rely on host machinery to replicate.

Question 33

What is the function of ER?

Answer 33

RER makes proteins, SER synthesizes lipids and detoxifies drugs.

Question 34

What does Golgi Apparatus do?

Answer 34

Modifies, stores, and packages materials for secretion or transport.

Question 35

What are lysosomes and why are they called suicide bags?

Answer 35

Enzyme-filled sacs that digest cell waste; they burst under stress and digest the cell.

Question 36

What is the function of mitochondria?

Answer 36

Generate energy in the form of ATP; called powerhouses of the cell.

Question 37

What are plastids?

Answer 37

Organelles in plant cells that store materials or perform photosynthesis.

Question 38

What is the difference between chloroplasts and leucoplasts?

Answer 38

Chloroplasts contain chlorophyll; leucoplasts store starch, oil, or proteins.

Question 39

What are vacuoles and what do they do?

Answer 39

Storage sacs; maintain turgidity in plants, store nutrients and waste.

Question 40

What is mitosis?

Answer 40

Cell division that results in two identical daughter cells; used in growth and repair.

Question 41

What is meiosis?

Answer 41

Cell division that produces four cells with half the number of chromosomes; used in reproduction.

Question 42

Why do gametes have half the number of chromosomes?

Answer 42

So that after fertilization, the full set is restored.

Question 43

Why do onion and human cells look different under the microscope?

Answer 43

Because they come from different organisms with different functions and structures.

Question 44

Why does water enter cells in hypotonic solutions?

Answer 44

Due to osmosis: water moves from low solute to high solute concentration.

Question 45

What would happen if there were no mitochondria?

Answer 45

The cell would not be able to produce energy and perform vital functions.

Question 46

How would a cell behave if its plasma membrane was completely permeable?

Answer 46

It would lose control over substance entry and exit, leading to imbalance and possible death.

Question 47

Why don’t prokaryotes need organelles like ER or Golgi?

Answer 47

Their functions are carried out by less specialized parts of the cytoplasm.

Question 48

Describe the parts of a compound microscope.

Answer 48

Eyepiece, objective lens, stage, coarse/fine adjustment, mirror, base, etc.

Question 49

What parts are visible in an onion peel under a microscope?

Answer 49

Cell wall, nucleus (stained), cytoplasm, rectangular structure.

Question 50

How does a plant cell diagram differ from an animal cell diagram?

Answer 50

Plant cell has cell wall, chloroplasts, large vacuole; animal cell does not.

Question 51

What does a prokaryotic cell diagram show?

Answer 51

Nucleoid, ribosomes, plasma membrane, cell wall, no defined nucleus.

Question 52

What does the diagram of mitosis show?

Answer 52

One mother cell dividing into two identical daughter cells.