Lecture 3 - Cells

Question 1

Which is the level of biological hiaerachy following atoms?

Answer 1

Cells

Question 2

How was the antibiotic penicillin discovered?

Answer 2

When Flemming discovered that bacteria could not approach a certain strain of fungi called penicillium, because it created penicillin

Question 3

What does the cells theory states?

Answer 3

That all living organisms are made up of more than one cell

That all cells come form other cells

Question 4

What are the 2 basic categories of cells, and what is the main structural difference between the 2

Answer 4

Eucaryotic (have a nucleus) and procaryotic (no nucleus, DNA in cytoplasm)

Question 5

Where do eucaryotic cells come from?

Answer 5

Invagination or endosymbiosis

Question 6

What is the process of invagination?

Answer 6

When the plasma membrane folds on itself to welcome an organelle

Question 7

What is the process of endosymbiosis?

Answer 7

When other procaryotic cells are engulfed by the plasma membrane of an eucaryotic cell, and the engulfed cell becomes an organelle

Question 8

What are the functions of the plasma membrane

Answer 8

• Take food/nutrients in
• Dispose of waste
• Build and export molecules
• Regulating heat exchange

Question 9

What is the phospholipid bilayer making the plasma membrane of all cells is made of?

Answer 9

1 portion of hydrophilic (polar) glycerol head

1 portion of hydrophobic (non polar) carbon/hydrogen tail

Question 10

What is the cell plasma membrane permeable to? and Impermeable to?

Answer 10

Permeable to : water and gasses

Impermeable to: larger polar/non polar molecules

Question 11

What is diffusion

Answer 11

Moving from clustered to diffused

Question 12

What is a solute?

Answer 12

What is dissolved

Question 13

What is a solvent?

Answer 13

Thing in which solute is dissolved

Question 14

What is simple diffusion?

Answer 14

Diffusions of small hydrophilic molecules (o2 and CO2) through the cell membrane

Question 15

What is facilitated diffusion?

Answer 15

Transport proteins make the diffusion of bigger, polar molecules easier through the cell membrane

Question 16

What is osmosis?

Answer 16

The passive distribution of water across the membrane

Question 17

What is the goal of osmosis?

Answer 17

Make a solution isotonic (water concentrations are equal inside and outside the cell)

Question 18

What is a hypotonic solution?

Answer 18

The concentration of solute is lower outside of the cell (water will enter the cell to balance)

Question 19

What is a hypertonic solution?

Answer 19

The concentration of solute is higher outside of the cell (water will exit the cell to balance)

Question 20

What is tonicity?

Answer 20

The difference of concentration between 2 solutions

Question 21

What is endocytosis/exocytosis?

Answer 21

The transport of particules in bulk (many at a time)

Question 22

What is phagocytosis

Answer 22

A cell engulfing another, creating a vesicle

Question 23

What is receptor-mediated endocytosis?

Answer 23

When particles have to bind to a specific receptor before being engullfed (ex: LDL in liver cells)

Question 24

What is pinocytosis

Answer 24

Same as phagocytosis but with smaller vesicles

Question 25

What is exocytosis?

Answer 25

When a transport vesicle fuses with the cell membrane and expulses the contents outside

Question 26

What are tight junctions? beteween which type of cell?

Answer 26

Animal cells; a water-tight seal between cells

Question 27

What are desmosomes?

Answer 27

Act like velcro that fastens cells together (not creating a water tight seal)

Question 28

What are gap junctions?

Answer 28

A type of cell junction that leaves a passage between the cells

Question 29

What is the nucleus? What are its functions?

Answer 29

The biggest organelle in the cell, contains DNA and its membrane is called the nuclear enveloppe

Question 30

What is the nucleolus?

Answer 30

It is where ribosomes are assembled (into the nucleus)

Question 31

What is the cytoskeleton?

Answer 31

Protein fibers that support cell movement in cells, made of microtubules (moving organelles around) and microfilaments (ex muscle fibers), intermediate filaments (giving rigidity to the cell) and cilia/flagella, that help the cell move around

Question 32

What is mitochondria?

Answer 32

Extract energy from food and oxygen and help the cell to function (basically an ATP factory) Made of intermembrane space and mitochondrial matrix

Question 33

What are lisosomes?

Answer 33

Cell's garbage disposal bins | Contain over 40 enzymes that digest substances

Question 34

What is the endomembrane system?

Answer 34

Its made of several organelles that produce/modify molecules to be brought to other parts of the cell

Question 35

What is the endomembrane system composed of?

Answer 35

The endoplasmic reticulum (rough and smooth); transport system (protein factory) The Golgi apparatus (shipping center for proteins)

Question 36

What are the plant-specific organelles?

Answer 36

Cell wall Vacuoles Chloroplasts

Question 37

What is the use of the cell wall

Answer 37

provides additional protection and support for plant cells (cellulose)

Question 38

What is the use of the Vacuoles

Answer 38

Storage units of many substances

Question 39

What is the use of the Chloroplasts

Answer 39

The site of photosynthesis

Question 40

What are the 2 types of active transport?

Answer 40

Primary (when ATP is used as fuel) | Secondary (when one molecule is moved against its concentration gradient using energy)

Question 41

What are the 2 types of membrane proteins

Answer 41

transmembrane (through the membrane) | surface (inside or outside)

Question 42

What are receptor proteins

Answer 42

attach with other cells or with chemicals

Question 43

What are recognition proteins

Answer 43

allows the immune system to differentiate between body cells and intruders cells

Question 44

What are transport proteins

Answer 44

help polar substances to pass through the membrane

Question 45

What are membrane enzymes

Answer 45

accelerate chemical reactions