Cellular Foundations

Question 1

What is a cell?

Answer 1

The structural and functional units of all living things.

Question 2

All cells are__________________

Answer 2

Surrounded by a plasma membrane that is made up of a lipid bilayer containing proteins

Question 3

What are the functions of the plasma membrane?

Answer 3

-defines rear periphery of the cell
-barrier to inorganic ions and most charger or polar organic compounds
-has transport proteins that allow passage of select ions and molecules
-receptor proteins that bind messengers
-enzymes catalyze various reactions

Question 4

What is the cytoplasm?

Answer 4

-includes the contents of the cell
-soluble, aqueous phase is termed the cytosol, which contains various particles with specific functions

Question 5

What is the nucleus?

Answer 5

-present in all cells at some stage of their life cycle
-stores and replicates the genome, consisting of DNA
-contains genetic material as chromosomes
-site of DNA replication, RNA synthesis
-contains a nucleolus- where ribosomal RNA and ribosomes are assembled
-surrounded by a membrane that has large nuclear pores

Question 6

Nucleus/Nucleoid

Answer 6

-termed nucleoid in Proks ( not separated by a membrane)
-termed nucleus in euks (surrounded by a membrane)

Question 7

What are the three distinct domains of life?

Answer 7

Bacteria- found everywhere: soil, water, in or on other organisms. etc
Archaea- found in extreme environments; hot springs, salt lakes
Eukaryotes- includes plants and animals. Contain distinct intracellular organelles with specific functions

Question 8

Explain the prokaryotic cell structure

Answer 8

-have a plasma membrane containing the cytosol
-cytosol contains ribosomes, small organic molecules, inorganic ions, etc.
-nucloid contains DNA (usually a circular single strand)
-most have plasmids

Question 9

Explain eukaryotic cell structure

Answer 9

-much larger than prokaryotes
-contain a distinct nucleus and other organelles with specific functions

Question 10

What does the mitochondria do?

Answer 10

-site of aerobic respiration and fatty acid oxidation
-surrounded by 2 membranes: outer, freely permeable and inner, limited permeability, forms folds called cristae. contains most of the enzymes for ATP synthesis
-have their own unique DNA
-inherited from mom, more plentiful than nuclear DNA, encodes for some of the mitochondria proteins
-probably arose from a symbiotic relationship with proks

Question 11

what do lysosomes do?

Answer 11

enzymes that degrade intracellular debris

Question 12

Explain the two endoplasmic reticulums.

Answer 12

Rough: site of much protein synthesis
Smooth: lipid synthesis and drug metabolism

Question 13

Explain the role of the Golgi

Answer 13

recesses, packages, and targets proteins to other organelles or for export

Question 14

Explain the role of peroxisomes

Answer 14

contain peroxidases, which destroy toxic H2O2
minor site of lipid oxidation

Question 15

What additional organelles are in plant cells?

Answer 15

Chloroplasts- harvest sunlight, produce ATP and carbohydrates
Cell wall-provides shape and rigidity
vacuole- varied functions, degrades macromolecules, stores metabolites
glyoxysome- allows plants to convert fats to carbohydrates

Question 16

How are organelles isolated to study?

Answer 16

sub cellular fractionation- different organelles with precipitate at different rates

Question 17

SUMMARY:
All cells are:
-enclosed by a ___________
-have _____ containing metabolites, coenzymes, inorganic ions, and enzymes
-have a set of genes contained in a _______ (bacteria and archaea) or a ________(eukaryotes)

Answer 17

-Plasma membrane
-cytosol
-nucleoid
-nucleus

Question 18

SUMMARY 2:
-Bacteria and Archaea contain _____, a _______, and _________
-Eukaryotic cells have a _____ and specialized _______, which can be separated and studied in the lab by ________
-Plant cells have additional, special organelles that allow them to synthesis ________ using energy from _________

Answer 18

-cytosol, nucleoid , plasmids
-nucleus, organelles , sub cellular fractionation
-macromolecules, sunlight