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Question 1

What is the fundamental structural and functional unit of all living organisms?

Answer 1

Cell

Anton Von Leeuwenhoek first saw and described a live cell.

Question 2

Who proposed the cell theory?

Answer 2

Schleiden and Schwann

Cell theory states that all plants or animals are composed of cells and their products.

Question 3

What does Rudolf Virchow’s contribution to cell theory state?

Answer 3

All cells arise from pre-existing cells (Omnis cellula-e cellula)

Modified the cell theory to include that all living organisms are composed of cells and products of cells.

Question 4

What are the smallest and largest isolated single cells?

Answer 4

Mycoplasma (0.3um) and ostrich egg

Cells differ greatly in size, shape, and activities.

Question 5

What is the main arena of cellular activities in both plant and animal cells?

Answer 5

Cytoplasm

Cytoplasm is where most cellular processes occur.

Question 6

What characterizes prokaryotic cells?

Answer 6

Lack membrane-bound nucleus and cell organelles

Represented by bacteria, blue-green algae, mycoplasma and PPLO (0.1um).

Question 7

What is plasmid?

Answer 7

Small circular DNA outside the genomic DNA in bacteria

In addition to genomic DNA, many bacteria have plasmids.

Question 8

What surrounds the cell membrane of prokaryotic cells?

Answer 8

Cell wall

All prokaryotes have a cell wall surrounding the cell membrane, except for mycoplasma.

Question 9

What is the structure of the prokaryotic cell envelope?

Answer 9

Three-layered structure: glycocalyx, cell wall, plasma membrane

Most prokaryotic cells have this tightly bound structure.

Question 10

What are mesosomes?

Answer 10

Extensions of plasma membrane into the cell

They help in cell wall formation, DNA replication, distribution of daughter cells, respiration, secretion process, and increase the surface area of plasma membrane.

Question 11

What are the surface structures of prokaryotic cells?

Answer 11

Flagella, pili, and fimbriae

Pili and fimbriae do not play a role in motility.

Question 12

What determines whether bacteria are motile or non-motile?

Answer 12

Presence of flagella

If motile, they have flagella composed of filament, hook, and basal body.

Question 13

How are bacteria classified based on staining?

Answer 13

Gram positive or Gram negative

This classification is based on the structure of their cell walls.

Question 14

What are ribosomes in prokaryotic cells?

Answer 14

Non-membrane bound organelles

Ribosomes are 70S, with subunits 50S and 30S.

Question 15

What is a polyribosome?

Answer 15

A chain of ribosomes attached to a single mRNA

This structure allows for simultaneous translation of mRNA.

Question 16

What are inclusion bodies?

Answer 16

Reserve material stored in prokaryotic cytoplasm

Examples include phosphate granules, cyanophyce granules, and glycogen granules.

Question 17

Where are gas vacuoles found?

Answer 17

In blue-green, purple, and photosynthetic bacteria

Gas vacuoles help bacteria maintain buoyancy.

Question 18

What defines eukaryotic cells?

Answer 18

Presence of a nucleus and other membrane-bound organelles

Includes protists, plants, animals, and fungi.

Question 19

What is the main composition of the cell membrane?

Answer 19

Proteins and lipids (mainly phospholipids)

Membrane proteins can be integral or peripheral.

Question 20

What is the fluid mosaic model?

Answer 20

Model for the structure of the cell membrane

Given by Singer and Nicolson in 1972.

Question 21

What property does the cell membrane have?

Answer 21

Selectively permeable

It controls the movement of substances in and out of the cell.

Question 22

What is the importance of the fluid nature of the membrane?

Answer 22

Cell growth, formation of intercellular junctions, secretion, endocytosis, cell division

Fluidity allows for lateral movement of proteins within the bilayer.

Question 23

What forms the cell wall in fungi and plants?

Answer 23

Non-living rigid structure

It forms an outer covering of the plasma membrane.

Question 24

What is the primary cell wall?

Answer 24

Capable of growth in young plant cells

Gradually diminishes as the cell matures.

Question 25

What is the secondary wall?

Answer 25

Formed on the inner side of the cell as it matures ## Footnote It provides additional strength.

Question 26

What is the middle lamella?

Answer 26

Layer mainly composed of calcium pectate ## Footnote It holds neighboring cells together.

Question 27

What are the components of the cell wall of algae?

Answer 27

Cellulose, galactans, mannans, calcium carbonate ## Footnote Different types of algae may have varying compositions.

Question 28

What are the components of the plant cell wall?

Answer 28

Cellulose, hemicellulose, pectin, proteins ## Footnote These components provide structural support.

Question 29

What is the endomembrane system composed of?

Answer 29

ER, Golgi complex, lysosomes, vacuole ## Footnote This system is involved in various cellular processes.

Question 30

What is the function of the rough endoplasmic reticulum (RER)?

Answer 30

Involved in protein synthesis ## Footnote The presence of ribosomes on its surface gives it a rough appearance.

Question 31

What is the function of the smooth endoplasmic reticulum (SER)?

Answer 31

Involved in lipid synthesis ## Footnote It lacks ribosomes and is smooth in appearance.

Question 32

What does the Golgi apparatus do?

Answer 32

Processes, packages, and transports materials for secretion ## Footnote It has cisternae that facilitate these functions.

Question 33

What do lysosomes contain?

Answer 33

Hydrolytic enzymes ## Footnote These enzymes break down waste materials and cellular debris.

Question 34

What is a vacuole?

Answer 34

A single membrane bound organelle found in the cytoplasm containing water, sap, excretory products, and other material not useful for the cell.

Question 35

What percentage of the volume of a plant cell does the vacuole occupy?

Answer 35

90%

Question 36

What type of organelles are ribosomes?

Answer 36

Non-membrane bound organelles

Question 37

What are the two types of ribosomes and where are they found?

Answer 37

80S in cytoplasm and 70S in mitochondria and chloroplasts

Question 38

What is the primary function of mitochondria?

Answer 38

Site of aerobic respiration producing cellular energy in the form of ATP

Question 39

What is the nickname given to mitochondria?

Answer 39

'Power house of the cell'

Question 40

What type of structure is each mitochondrion?

Answer 40

A double membrane bound structure

Question 41

What does the mitochondria contain?

Answer 41

Single circular DNA molecule, a few RNA molecules, ribosomes (70S), and components for protein synthesis

Question 42

Where are plastids found?

Answer 42

In all plant cells and in euglenoids

Question 43

What pigments do chloroplasts contain?

Answer 43

Chlorophyll and carotenoid pigments

Question 44

What are leucoplasts?

Answer 44

Colorless plastids

Question 45

What do amyloplasts store?

Answer 45

Carbohydrates

Question 46

What do elaioplasts store?

Answer 46

Oils and fats

Question 47

What do aleuroplasts store?

Answer 47

Proteins

Question 48

What type of structure are chloroplasts?

Answer 48

Double membrane bound structure

Question 49

What does the stroma of chloroplasts contain?

Answer 49

Small, double stranded circular DNA molecules and ribosomes (70S)

Question 50

What is the cytoskeleton?

Answer 50

An elaborate network of filamentous proteinaceous structures present in the cytoplasm

Question 51

What are the functions of the cytoskeleton?

Answer 51

* Mechanical support * Motility * Maintenance of the shape of the cell

Question 52

What are cilia and flagella?

Answer 52

Hair-like outgrowths of the cell membrane

Question 53

What is the central core in cilia and flagella called?

Answer 53

Axoneme

Question 54

What is the arrangement of microtubules in axoneme?

Answer 54

9 + 2 array of microtubules

Question 55

From what structure do both cilia and flagella arise?

Answer 55

Basal bodies

Question 56

What is a centrosome?

Answer 56

An organelle usually containing two cylindrical structures called centrioles

Question 57

What is the arrangement of microtubules in centrioles?

Answer 57

9 + 0 array of microtubules

Question 58

What do centrioles form?

Answer 58

* Basal body of cilia or flagella * Spindle fibres that give rise to spindle apparatus during cell division in animal cells

Question 59

Who discovered the nucleus?

Answer 59

Robert Brown

Question 60

What is chromatin and who named it?

Answer 60

Chromatin is the material in the nucleus, named by Flemming

Question 61

What does the interphase nucleus contain?

Answer 61

* Chromatin * Nuclear matrix * Nucleolus

Question 62

What is the space between the two membranes of the nucleus called?

Answer 62

Perinuclear space

Question 63

What does the nuclear matrix or nucleoplasm contain?

Answer 63

* Nucleolus * Chromatin

Question 64

What does chromatin consist of?

Answer 64

* DNA * Basic histones * Non-histones * RNA

Question 65

What is a primary constriction on every chromosome called?

Answer 65

Centromere

Question 66

What structures are present on the sides of the centromere?

Answer 66

Disc-shaped structures called kinetochores

Question 67

What are microbodies?

Answer 67

Membrane bound minute vesicles which contain enzymes

Question 68

In which types of cells are microbodies present?

Answer 68

Both plant and animal cells