week 2 Flashcards
(19 cards)
whats the primary endosymbiotic theory?
- A prokaryotic cell engulfed another but did not digest it
- Overtime, the engulfed cell became an organelle inside the host
- This process lef to the evolution of chloroplasts from cyanobacteria, giving rise to photosynthetic eukaryotic cells (plant and algae)
function and structure of the nucleus
Function
- Control center of the cel
- Contains and protects DNA
- Instructions for building proteins
Structure
- Doiuble membrane
- Nucleolus
- Chromosomes
function and structure of cell membrane
Function
- Separates cell from environment
- Controls what enters or leaves cell
- Recognizes signals from other cells
Structure
- Phospholipid bilayer
what are the cells 3 main jobs?
◆ Produce energy
▪ need energy for all activities
▪ need to clean up waste produced
while making energy
◆ Synthesis proteins
▪ proteins do all the work in a cell,
so we need lots of them
◆ Make more cells
▪ for growth
▪ to replace damaged or diseased cells
what is ploidy and what are diploid and haploid cells
Refers to the number of sets of chromosomes in cells
Diploid: two sets of chromosomes (2n), in humans 23 pairs or 46 total
Haploid: one set of chromosomes (n) – gamete or sex cells , in humans 23 chromsomes
describe eukaryotic cell division
Interphase
- G1, S, G2 phases
Prophase
- Cell prepares for nuclear division
- Chromosomes appear
- Centrioles separate and spindles form
- Nuclear envelope disappears
- Spindle fibers attach to centromere of each chromosome
- Longest phase in mitosis
Metaphase
- Chromosomes line up at middle of cell
- Spindle fibers attach to chromosomes at the centromere
Anaphase
- Spindle fibers pull chromosomes apart
- ½ of each chromosome (called sister chromatid) moves to poles of cells
Telophase
- Dna uncoils and appears as chromatin
- 2 nuclei form
- New cell wall forms between 2 nuclei to form the 2 new daughter cells
Cytokinesis
- Means division of the cytoplasm
- Division of cell into 2 identical halves called daughter cells
- In plant cells cell plates from at the equator to divide cell
what is meiosis and its importance
Meiosis
- A single germ cell divides into 4 unique daughter cells
- Cell division that reduces the chromosome number by half
- Essential for sexual reproduction in algae and ensures genetic diversity
Importance:
- Produces haploid gametes for sexual reproduction
- Ensures genetic variation through recombination
- Essential for alternation of generations in many alga
If meiosis did not occur the chromosome number in each new generation would double and the offspring would die
describe the process of meiosis
Interphase 1
- Chromosomes replicate (s phase)
- Each duplicated chromosome consist of 2 identical sister chromatids attached at their centromeres
- Centriole pairs also replicate
Prophase 1 :
- Chromosomes condense
- Homologous chromosomes pair eachother
- Each pair contains 4 sister chromatids
- Crossing over occurs
Metaphase 1
- Homologous chromosomes move to center of cell
Anaphase
- Homologous chromosomes pulled to opposite poles
Telophase
- Daughter nuclei formed
-
- These are haploid
Meisosis 2:
there are no replications of chromosomes metaphase 2 takes place but they line up single file then anaphase, telophase and cytokinesis takes place.
chromosome number is half of the parent cell
meiosis and alteration of generations in algae
- Many algae exhibit an alternation of generations, where meiosis plays a key role:
- Sporophyte (2n) undergoes meiosis, producing haploid spores (n)
- Spores develop into haploid gametophytes (n), which produce haploid gamete through mitosis
- Gametes fuse (fertilization) to restore the diploid sporophyte.
nutrient assimilation
- algae absorb nutrients from water for growth
carbon fixation - converts inorganic CO2 into organic carbon via the calvin cycle
> nitrogen metabolism - uses nitrate or ammonium for protein and enzyme production. Some cyanobacteria fix nitrogen from the atmosphere
> phosphorus uptake - absorbs phosphates for ATP, DNA and membrane formation.
what are the laws of thermodynamics
> first law (conservation of energy)
Energy cannot be created or destroyed – only transformed
Second law
Energy changed are not 100% efficient
Energy conversion increase disorder or entropy
Some energy is always lost as heat
what are two types of metabolic processes
Catabolic = breakdown:
- Generation of energy and reducing power from complex molecules
- Produces small molecules for use and as a waste products
Anabolic = biosynthesis
- Contruction of large molecules to serve as cellular components such as amino acids fr proteins nucleic acids, fats
- Consumes energy
what’s an exergonic and endergonic reaction
exergonic reaction- releasing free energy
endergonic- requires the input of free energy
whats cellular respiration
- process by which cell convert glucose into ATP
whats ATP used for
- Used for cellular metabolic processes
- Eg = active transport of molecules across the cell membrane
- Protein synthesis
- Muscle contractions
summary of glycolysis
- Takes place in cytoplasm
- Anaerobic
- Requires input of 2 ATP
- Glucose split into 2 molecules of pyruvate
- Also produces 2 NADH and 4 ATP
After glycolysis
- Here the pyruvate molecule reacts with Coenzyme A (CoA) and is converted into acetyl CoA (C2 molecule)
- 2 NADH and 2 CO2 molecules are also produced.
summary of the krebs cycle
- Starts when 2 acetyl CoA molecules enter the matrix of the mitrochondrion
- One ATP molecule per cycle
- Requires oxygen
- Turns twice per glucose molecule
- Produces 2 ATP
- Takes place in mateix of mitochondria
- Therefore for each glucose molecule the krebs cycle produces 6NADH, 2FADH2, 4CO2, and 2 ATP
summary on the electron transport chain and some information on ATP synthase
- Located in the inner membrane of the mitochondria
- Oxygen pulls the electrons from NADH and FADH2 down the ETC to a lower energy state
- Process produces 32 ATP or 90% of the ATP in the body
- Requires oxygen, the final electron acceptor.
- For every FADH2 molecule – 2 ATP’s are produced.
- For every NADH molecule – 3 ATP’s are produced.
ATP synthase
- A protein in the inner membrane in the mitochondria
- Uses energy of the ion gradient to power ATP synthesis
- For every H+ ion that flows through ATP synthase, one ATP can be formed from ADP
describe fermentation or anaerobic respiration in algae
- Occurs in low – oxygen conditions (deep water, dense algal blooms, sediments)
- Less efficient (produces only 2 ATP per glucose molecule)
- Produces byproducts like ethanol, lactic acid, or hydrogen gas
- Lactic acid fermentation (the pyruvate is reduced to lactate)
*Alcoholic fermentation (the pyruvate is reduced to alcohol and CO2) - Carbs fats and proteins can be all catabolized to produce ATP
