Intro to Cell Biology

Question 1

Cell Theory

Answer 1

• All organisms are composed of cells
• The cell is the fundamental unit of life
• All cells arise from other cells

Question 2

Scientists who developed the cell theory:

Answer 2

Schleidan, Schwann, and Virchow (1800s)

Question 3

A modern definition of the cell:

Answer 3

The basic unit from which organisms are made, consisting of an aqueous solution of organic molecules enclosed by a membrane.
All cells arise from existing cells, usually by a process of division.

Question 4

Three Domains:

Answer 4

Bacteria, Archaea, Eukarya

Question 5

Defining features of Domain Eukarya:

Answer 5

True nucleus (membrane bound); membrane-bound organelles; exo-/endocytosis; linear DNA bound to histones, arranged in chromosomes; cell division via mitosis and meiosis; regulation of gene expression

Question 6

Organelles

Answer 6

Internal membranes compartmentalize specific functions

Question 7

Plasma membrane

Answer 7

Defines cell boundaries and retains contents

Question 8

Mitochondria

Answer 8

Site of aerobic respiration
Found in all eukaryotic cells
Tissues with high energy demands have more mitochondria

Question 9

Chloroplast

Answer 9

Site of photosynthesis in plants and algae

Question 10

The Endosymbiont Theory

Answer 10

Mitochondria and Chloroplasts evolved from a symbiotic relationship between ancient bacteria (aerobic and/or photosynthetic) and early eukaryotic cells
Evidence:
circular DNA (like bacteria)
replication occurs separate from the cell
Double membrane

Question 11

Endoplasmic Reticulum

Answer 11

A network of membranes found in the cytoplasm

Composed of cisternae - tubular membranes and flattened sacs

Question 12

Smooth ER

Answer 12

Site of lipid synthesis

Question 13

Rough ER

Answer 13

Embedded with ribosomes

Site of protein synthesis

Question 14

Golgi Complex

Answer 14

Stack of flattened vesicles known as cisternae
Synthesis of complex polysaccharides
Processing and packaging of secretory proteins

Question 15

Lysosomes

Answer 15

Single membrane organelles which store hydrolases - enzymes that can digest biological molecules
A special carbohydrate lining protects lipid membrane from hydrolases - need to keep hydrolases contained in order to not digest cell

Question 16

Peroxisome

Answer 16

Single membrane organelle

Performs several functions depending on cell type

Question 17

Ribosomes

Answer 17

They are not organelles - they are not membrane bound

Complexes of proteins and nucleic acids which synthesis proteins in translation

Question 18

Cytoplasm

Answer 18

Defined as the interior of the cell not including the nucleus
Contains the cytosol (semifluid substance in which organelles are suspended) as well as organelles, and the cytoskeleton

Question 19

Cytoskeleton

Answer 19

A three- dimensional array of interconnected microfilaments, microtubules, and intermediate filaments

Question 20

Extracellular Matrix

Answer 20

Structures outside of the cell membrane; consists mainly of collagen fibers and proteoglycans

Question 21

Challenges of imaging living cells and subcellular constituents:

Answer 21

Resolution
Contrast
Preservation
Three-dimensionality

Question 22

Examples of Model Organisms

Answer 22

E. coli (bacteria). S. cerevisiae (yeast), mice, C. elegans (nematode), Drosophila (fruit fly), Arabidopsis

Question 23

Types of Light Microscopy:

Answer 23

Brightfield (unstained and stained), Fluorescence, Phase Contrast, Differential Interference Contrast, Confocal

Question 24

Fluorochromes

Answer 24

Absorb light at one wavelength and re-emit light an a longer wavelength