CELL: THE UNIT OF LIFE

Flashcards based on lecture notes about cells.

What is the study of cells called?

Cytology

What are organisms made up of?

One or more cells

What is the significance of a unicellular organism?

It has independent existence and performs essential functions of life.

What is the building block of living organisms?

Cell

Who observed the first dead cell in a cork slice?

Robert Hooke

Who observed the first living cell?

Anton Von Leeuwenhoek

Who discovered the nucleus?

Robert Brown

Who proposed that all plants are composed of different cells that form tissues?

Schleiden

Who proposed that animal cells have a thin outer layer called the plasma membrane?

Schwann

Who completed the cell theory by stating that all cells arise from pre-existing cells?

Rudolf Virchow

What is the meaning of "Omnis cellula e cellula"?

All cells arise from pre-existing cells.

What is the largest known cell?

Egg of an Ostrich

What is the smallest cell?

Mycoplasma

What is the longest cell?

Nerve cell

What is the function of the semi-fluid matrix in the cell?

The main arena of cellular activities where chemical reactions occur.

What does protoplast refer to?

A cell without a cell wall, only plasma membrane and internal cellular components

What is protoplasm?

Living substance within a cell (cytoplasm + nucleoplasm)

What is a eukaryotic cell?

Cell having membrane-bound nuclei

What are examples of membrane-bound organelles?

Nucleus, Mitochondria, Plastid, ER, Golgi body, lysosome, vacuoles

What is a prokaryotic cell?

Cells that lack a membrane bound nucleus

What is the function of plasmids?

Confer unique characters such as resistance to antibiotics and are used in bacterial transformation with foreign DNA.

What are the three layers of the cell envelope?

Glycocalyx, Cell Wall, Plasma Membrane

What is the function of Glycocalyx?

Protects cells and helps in adhesion.

What is the function of the cell wall?

Gives shape and structural support, preventing cells from bursting or collapsing.

What is peptidoglycan?

The building block for the cell wall.

What is Gram staining used for?

To classify Gram-positive and Gram-negative bacteria.

What is the function of the plasma membrane?

Selectively permeable and interacts with the outside world.

What is the mesosome?

A special membranous structure formed by invagination of the plasma membrane into the cell.

What is the function of the mesosome?

Formation of cell wall, replication of DNA, cell division, respiration, secretion

What are chromatophores?

Membranous extensions into the cytoplasm that contain pigments (e.g., in cyanobacteria).

What is the composition of flagella?

Filament, Hook, and Basal body

What is the composition of prokaryotic flagella?

Flagellin protein

What is the composition of eukaryotic flagella?

Tubulin protein

What is the role of pili?

Help in conjugation (transfer of plasmid from one bacterium to the other).

What is the function of fimbriae?

Attachment

What is the function of ribosomes?

Site of protein synthesis.

What is a polysome?

A chain of ribosomes attached to a single mRNA.

What are inclusion bodies?

Non-membrane bound structures that store materials in the cytoplasm.

What is genophore?

The genetic material of prokaryotic cells (DNA).

What are the key differences between prokaryotic and eukaryotic cells?

Cell size, presence of a nuclear membrane, number of chromosomes, presence of a nucleolus, and presence of membrane-bound organelles

In cell membrane, what part is water-fearing

Hydrophobic Non-polar tail

Name Singer and Nicolson contribution to cell membrane

Proposed Fluid mosaic model of plasma membrane - in 1972

Fluid mosaic model states that membrane made up of:

Protein, Carbohydrate, Lipid

What the location of hydrophilic membrane part:

Outside

What is Lateral and Flip-Flop

Types of phospholipid movements in membrane

Protein movements, regarding Flip-Flop

No Flip-Flop movment due to the large size

Plasma membrane is:

Asymmetrical

Define Passive transport in cell membrane

No energy needed, osmosis an diffusion, follows concentration gradient

Define Active transport in cell membrane

Need energy ATP, goes against concentration gradient

Define Endocytosis

Intake of materials in the form of Carrier vesicles formed by invagination plasma membrane

Two types of endocytosis:

Pinocytosis and Phagocytosis

Define Exocytosis

Discharge undigested waste products to outside of the cell through plasma membrane, AKA Cell vomiting / Ephagy

Composition of cell wall - Bacteria

Peptidoglycan

Composition of cell wall - Fungi

Chitin

Composition of cell wall - Algae

Cellulose, galactans, mannans and minerals like calcium carbonate

Composition of cell wall - Plant

Cellulose, Hemicellulose Pectin and proteins

Endomembrane System includes

Endoplasmic reticulum, Golgi complex, Lysosome, Vacuoles

What is Extends From nuclear membrane to plasma membrane

Endoplasmic Reticulum

ER is composed of

Cisternae, Tubules, Vesicles

Where are actively protein synthesis cells found:

Pancreas and brain cell

Ribophorin-I and Ribophorin - II locations:

Cisternae

Lipid and sterol synthesis locations:

Tubules

Muscle cell sarcoplasmic reticulum

SER. Smooth Endoplasmic Reticulum

Camillo golgi observed:

Golgi apparatus

cis Face of Golgi apparatus:

Take unmodified protein

Trams Face of Golgi apparatus:

After modification protein discharged From the trans Face

Golgian Vacuoles with hydrolytic enzyme is Called

Lysosome

Acidic condition of lysosome maintained by

H+ ATPase Pump

Multiple Forms of lysosomes known as

polymorphism

Tonoplast

Single membrane bound that surrounds Vacuole

Mitochondria Shape

cylindrical or Sausage

Janus green stains

Mitochondria

ATP is made mainly in Mitochondria or outer membrane

Inner membrane

Diameter of mitochondria

0.2 to 1.0 μm

length of mitochondria

1.0 to 4.1 μm

Protein factories

Ribosomes

George Palade C1953 discovered

Ribosomes

Svedberg unit measures:

ribosome on density

Plastids are

Found in eukaryotic autotrophs like Plant and Euglenoides

Leucoplasts

Colourless, occur near nucleus in non-green cell, store starch.

Elaioplasts

Store Fats and oil

Aleuroplasts

Store proteins

Chromoplasts

Contain carotene, xanthophylls like pigment

Chloroplasts

Possess photosynthetic pigments

Where are chloroplasts Found:

Mesophyll cells of leaves

Thylakoid membrane is analogous to:

cristae in mitochondria

Cytoskeleton composition

Microtubules, Micro Filaments, Intermediate Filament proteinaceous structure

Cartwheel like organization

Centrosome

Basal bodies rise from

Centrioles

cillia and Flagella internal organization is:

similar in Eukaryot

Microbodies types:

Sphaerosome, Glyoxysomes, Peroxisomes

Sphaerosome function:

Storage and synthesis of fats, AKA Plant lysosomes

Spherical sac-like structure Found in both plant and animal cell, contain enzymes

Peroxisomes

Double membrane bound structure brain of cell is

Nucleus

Flemming discovered:

Chromatin

Lack of nucleus state called

Anucleate

Two nuclei per cell state called

Binucleate

Many nuclei state called

Multinucleate

rRNA factory is

Nucleolus

Lampbrush chromosome discovered by

J. Ruckert