WK2 Cell Bio

winniesmith's version from 2017-01-03 11:19

Section 1

Question Answer
Two types of cell Prokaryotic(bacteria)-lack of nuclear envelope. Eukaryotic-have a nucleus that separates genetic material from cytoplasm.
Differences between the two types of cellProkaryoticNucleus absent, smaller cell(1um), cytoplasmic organelles absent. Less DNA content 1x10^6-5x10^6. Single circular chromosome.
Differences between the two types of cellsEukaryoticNucleus present, larger cell (10-100um). Cytoplasmic organelles present. More DNA content 1.5x10^7 to 5x10^9. Multiple linear chromosomes.
What do all present day cells descend from?a single primordial ancestor, around 3.8 million years ago by spontaneous formation of organic molecules.
How did macromolecules form?MAY have formed by spontaneous polymerization (shown using plausible prebiotic conditions). Critical characteristic of the macromolecule from which life evolved was its ability to replicate itself.
What are nucleic acids capable of?Self replication
What did Altman and Cech discover?That RNA is capable of catalyzing chemical reactions, including the polymerization of nucleotides. RNA is generally believed to have been initial genetic systems in evolution (RNA world).
How does RNA replicate?RNA is able to both serve as a template for, and to catalyze its own replication.

Section 2

Question Answer
What genetic material do all present day cells use?DNA, and have the same mechanisms for replication and gene expression.
What are genes?are segments of DNA that encode proteins or RNA- function units of inheritance.
What is transcription?nucleotide gene sequence is copied into RNA.
What is translation? nucleotide sequence of RNA is used to specify the order of amino acids in a protein.
What biological membranes made of?phospholipids membrane.
How are phospholipids are amphipathic?They have hydrophobic hydrocarbon chains (tails) are joined to hydrophillic water-soluble head groups that contain phosphate. When placed in water,phospholipids spontaneously aggregate into a bilayer.
What is the evolve mechanisms for generating energy and synthesizing molecules?Use adenosine 5'-triphosphate(ATP) - source of metabolic energy.
The mechanisms of generation of ATP glycolysis, photosynthesis and oxidative metabolism.
When did Glycolysis evolve?When earths atmosphere was anaerobic (All present-day cells carry out glycolysis).
What is glycolysis?Glucose is broken down to lactic acid, with 2 ATP gained.
Why did photosynthesis evolve?It allowed some cells to harness energy from sunlight: they no longer needed preformed organic molecules.
What did the first photosynthetic bacteria use?H2S to convert CO2 to organic molecules- a pathway still used by some bacteria. Use of H2O in photosynthesis evolved later; it changed earths atmosphere by making free O2 available.

Section 3