Week 1: Intro and Cell Basics

Question 1

What are characteristics of a cell?

Answer 1

plasma membrane surrounding cytoplasm, DNA, ribosomes + protein systems, unicellular or multicellular, and they reproduce.

Question 2

What is the cell theory?

Answer 2

fundamental unit of life, all living things are composed of cells (and cell products), all cells evolved from common ancestor, all cells come from other cells

Question 3

What are the two groups of prokaryotes

Answer 3

Eubacteria and archaebacteria

Question 4

What shapes do prokaryotic cells take form of?

Answer 4

Spheres, rods or spirals.

Question 5

What are the components of prokaryotic cell?

Answer 5

Surrounded by envelope of inner plasma membrane, peptidoglycan cell wall and sometimes a lipopolysaccharide outer membrane. No nucleus, DNA is found in a distinct area.

Question 6

What are characteristics of eukaryotic cell?

Answer 6

Some are single celled, others are multicellular. Have a nucleus and other membrane closed organelles.

Question 7

What are the types of eukaryotes?

Answer 7

Plant, animal, fungi, protists, other complex unicellular organisms

Question 8

What is the plasma membrane?

Answer 8

Surrounds cell, phospholipid bilayer embedded with proteins and may be covered with carbs, communicates with other parts of cell by vesicle endo and exocytosis

Question 9

What is the nucleus?

Answer 9

Enclosed in two concentric membranes - nuclear envelope -perforated by nuclear pores - contains most of DNA - DNA and protein combine to form chromatin, become visible as chromosomes, may have prominent nucleoli (where rRNA is being made)

Question 10

What are mitochondria?

Answer 10

Harness energy from chemical compounds and convert it into ATP. Enclosed in two separate membranes with inner formed into folds (where ATP is generated) and the outer.
Have own DNA and reproduce by division..

Question 11

What are chloroplasts?

Answer 11

Found in plants and algae. Have two surrounding membranes and the inner membrane possesses internal stacks containing green pigment chlorophyll. Carry out photosynthesis (using sunlight to create sugar molecules). Have own DNA.

Question 12

What is the ER?

Answer 12

Endoplasmic Reticulum - maze of interconnected spaces enclosed by membrane - continuous with membranes of nuclear envelope. Most cell components are made here.

Rough ER is studded with ribosomes (translates RNAs into proteins)

Smooth ER has no ribosomes - synthesizes and stores lipids

Question 13

What is the Golgi Apparatus?

Answer 13

Stacks of flattened membrane-enclosed discs (not interconnected). Connects to other organelles through vesicles. Near nucleus. Modifies and packages molecules made in ER.

Question 14

What is the Cytosol?

Answer 14

Part of cytoplasm not contained within intracellular membranes - largest single compartment in most cells. Is a host of large and small molecules crowded together - behaves like a water-based gel (is aqueous). Site of chemical reactions.

Question 15

What is the Cytoskeleton?

Answer 15

Responsible for cell movements (both whole cell and intracellular molecular movements). Supports cell shape and gives it strength. Actin filaments, microtubules and intermediate filaments.

Question 16

Compare prokaryotic and eukaryotic cells.

Answer 16

Eukaryotes have a nucleus, are 10 to 100x larger, have an elaborate cytoskeleton (where prokaryotes have a primative one), they have membrane bound organelles, have 15-1000 times more DNA, and have multiple linear DNA molecules rather than single circular one in prokaryotes.

Question 17

What are the essential steps in cell evolution?

Answer 17

development of macromolecules and self-replication.

Question 18

When did the first cells arise?

Answer 18

3-4 bya

Question 19

What developed before DNA and protein?

Answer 19

RNA with catalytic properties (riboenzymes)

Question 20

What is the RNA World Hypothesis?

Answer 20

Enclosure of RNA within phospholipid membrane, development of RNA-directed protein synthesis, development of metabolism, development of DNA as hereditary material with RNA intermediary.

Question 21

What were some of the earliest cell forms?

Answer 21

Cyanobacteria formed stromatoliths (still being formed today), produced abundant oxygen.

Question 22

What caused the initial development of eukaryotes?

Answer 22

Prokaryotes arose first. Initial development of eukaryotes may have arose by internalization of membranes to form membrane-bound nucleus and ER.

Question 23

What is the endosymbiont theory?

Answer 23

Anaerobic prokaryotes evolved into eukaryotes when aerobic prokaryotes were engulfed - mitochondria and chloroplasts - lived symbiotically within engulfing cell.