A Tour of the Cell

Question 1

Theory:

Answer 1

1. All organisms are composed of cells
2. Cells are the smallest living things
3. Cells arise only from pre-existing cells

Question 2

Cell size is limited

Answer 2

Most cells are relatively small due to reliance on diffusion of substances in and out of cells

Question 3

Rate diffusiom after by:

Answer 3

1. Surface area
2. Temperature
3. Concentration gradient
4. Distance

Question 4

Surface area-to-volume ratio:

Answer 4

Organism made of many small cells has an advantage over an organism composed of fewer, larger cells

Question 5

As a cell’s size increases ..

Answer 5

It’s volume increases much more rapidly than its surface area

Question 6

Some cells overcome limitation ..

Answer 6

By bring long & skinny - like neutrons

Question 7

Microscopes:

Answer 7

Not many cells are visible to the naked eye

-most are less than 50 ü m in diameter

Question 8

Resolution:

Answer 8

Minimum distance 2 points can be apart & still be distinguished as two separate points
-objects must be 100 ü m apart for the naked eye to resolve them as 2 objects rather than one.

Question 9

Light microscopes:

Answer 9

1. Use magnifying lenses wuth visible light
2. Resolve structures that are 200 nm apart
3. Limit to resolution using light

Question 10

Electron microscope:

Answer 10

1. Use beam of electrons

2. Resolve structures that are 0.2 nm apart

Question 11

Scanning electron microscope (SEM):

Answer 11

Scans the surface

Question 12

Transmission electron microscope (TEM):

Answer 12

Slices in between the structures & shows a picture of the interior

Question 13

Basic features of ALL cells:

Answer 13

1. Plasma membrane
2. Semi fluid substance called cytosol
3. Chromosomes (carry genes)
4. Ribosomes (make proteins)

Question 14

Prokaryotic cells:

Answer 14

1. Simplest organisms
2. Lack a membrane- bound nucleus
   - DNA is present in the nucleoid
3. Cell wall outside of plasma membrane (protect the cell, maintain its shape, & prevent excessive uptake or loss of water)
4. Do contain ribosomes (not membrane-bound organells)

Question 15

2 domains of prokaryotes:

Answer 15

1. Archaea

2. Bacteria

Question 16

Eukaryotic cells:

Answer 16

1. Possess a membrane-bound nucleus
2. More complex than prokaryotic cells
3. Possess a cytoskeleton for support and maintain cellular structure

Question 17

Hallmark is compartmentation ..

Answer 17

Achieved through use of membrane-bound organelles & endomembrane system

Question 18

Nucleus:

Answer 18

Houses genetic information

Question 19

Nucleolus:

Answer 19

Region where rRNA synthesis takes place

Question 20

Nuclear envelope:

Answer 20

Double membrane structure that surrounds the nucleus in eukaryotic cells & provides this compartmentalization.

Question 21

Chromatin:

Answer 21

DNA + Protein

Question 22

Ribosomes:

Answer 22

Cell’s protein synthesis machinery

Question 23

Ribosomes are found in ..

Answer 23

All cell types in all 3 domains

Question 24

Ribosomal RNA (rRNA) is ..

Answer 24

Protein complex

Question 25

Ribosomes may be free in ..

Answer 25

Cytoplasm or associated with internal membranes.

Question 26

Endomembrane system:

Answer 26

1. Series of membranes throughout the cytoplasm 2. Divides cell into compartments where different cellular fuctions occur 3. 1 of the fundamental differences between eukaryotes and prokaryotes

Question 27

Rough endoplasmic retuculum (RER):

Answer 27

Synthesis of proteins to be secreted, sent to lysosomes or plasma members

Question 28

Smooth endoplasmic reticulum (SER):

Answer 28

Variety of functions (lipid synthesis, store Ca2+, detoxification)

Question 29

Golgi Apparatus:

Answer 29

1. Flattened stacks of interconnected membranes (golgi bodies) 2. Cis & trans faces 3. Vesticles transport molecules to destination

Question 30

Golgi Apparatus have functions in ..

Answer 30

Packaging & distribution of molecules synthesized at 1 location & used at another location within the cell or even outside it

Question 31

Lysosomes:

Answer 31

Membrane-bound digestive vesticles

Question 32

Lysosomes arise from:

Answer 32

Golgi Apparatus

Question 33

Lysosomes enzymes catalyze:

Answer 33

Breakdown of macromolecules

Question 34

Lysosomes destroy ..

Answer 34

Cells or foreign matter that the cell has engulfed by phagocytosis.

Question 35

Cells were discovered in _____ by _____

Answer 35

Cells were discovered in 1665 by Robert Hooke. Early studies of cells were conducted by Mathias Schleiden & Theodor Schwann who proposed the cell.