Patterns of Inheritance

Who was Gregor Mendel?
Gregor Mendel was the first "geneticist" to figure out a concrete law on inheritance. He was a monk in what was then Austria, working with the inheritance of pea plants. 

Are there diseases that are genetically transmittable?
Yes, many in fact. Thankfully most are recessive, due to evolution, ones that are dominant have mostly killed off their hosts.

What is incomplete dominance? 
A condition in genetics that causes both, blended or some traits of the parents to appear in the offspring.

The Facts: 
-The Law of Segregation is: A sperm or egg carriers only one allele for each inherited character because allele pairs separate from each other during the production of gametes
-The Law of Independent Assortment is: Each pair of alleles segregates independently of other pairs of alleles during gamete formation.
-The Rule of Multiplication is: 1/2*1/2 = 1/4, which is true for genetics when it comes to recessive traits
-The Rule of Addition is used to figure out the probability of certain phenotypes (Aa and AA produce the same phenotype)
-"Carriers" refers to those who carry a recessive gene for a disorder, but do not show signs of said disorder
-Cystic fibrosis is one of said diseases, which causes mucus to be produced in excess in many places in the body, including the lungs
-Chromosome Theory of Inheritance: Genes occupy specific loci on chromosomes and chromosomes that undergo segregation and independent assortment during meiosis.
-Recombination frequency is when the offspring have the phenotype of the parent.
-Sex-linked genes are ones that are specifically on the sex chromosomes, usually on the X
-Red-Green Color blindness is attached to the X, and is much more common in males, since they only have one. Females, having two, have the chance of having a non-affected X, which allows them full color vision.

Some Helpful Terms:
-Character: A heritable feature that varies among individuals
-Trait: A variant of a character
-Homozygous: Two of the same allele
-Heterozygous:  Two different alleles
-Phenotype: The physical traits
-Genotype: The genetic make-up
-Testcross: Mating between an individual of unknown genotype and homozygous recessive to figure out the genetic make up of the other
-Inbreeding: Mating of closely related organisms
-Codominant: Both alleles are expressed in a heterozygous individual
-Pleiotropy: Genes that affect more than one character

Diagram:

This is an example of a Punnett square, for the shape and color of peas. It is apparent that green and wrinkled are the recessive traits, while smooth and yellow are dominant. About 1/4 will be green, and 1/4 will be wrinkled- this being an example of the rule of addition. On that note, only 1/16 will be green AND wrinkled (rule of multiplication).








Summary:
This chapter discusses one of the coolest facets of biology- genetics and inheritance. GO GENETICS! But it starts off talking about Gregor Mendel, and how he came to study genetics. He was very meticulous in controlling which plants bred with which, giving some very concrete data. The punnett square was crucial in the field of genetics, giving us a good way of seeing how genetic variation operates.
Not only that, but it goes on to talk about the things that Mendel didn't know, such as incomplete dominance, co-dominance and sex linked genes.

A Cool Video:
http://www.youtube.com/watch?v=oVl8OH_7QSc

Photosynthesis: Using Light to Make Food

What is the equation for photosynthesis?

6CO2 + 6H2O --> (Light Energy) --> C6H12O6 + 6O2

What is the difference between photosynthesis and the Calvin cycle?

The Calvin cycle doesn't require sunlight.

What does the Calvin cycle produce?

Sugars: Cellulose, Starch and other organic compounds.

The Facts:

-The Calvin cycle doesn't require sunlight
-Plants are known as producers because they create their own energy
-Another word for producers is autotrophs
-Photosynthesis is similar to cell respiration in that it's how the cell produces energy
-Without photosynthesis, cell respiration couldn't occur, as photosynthesis creates oxygen for it
-Similarly, without cell respiration, photosynthesis couldn't occur, as it requires the carbon dioxide that cell respiration gives off
-The energy released by electrons is conserved as it is passed from one molecule to another.
-Cellular respiration uses redox reactions to harvest the chemical energy stored in a glucose molecule.
-Chemiosmosis is the mechanism that not only is involved in oxidative phosphorylation in mitochondria but also generates ATP in chloroplasts
-ATP synthase couples the flow of H+ to the phosphorylation of ADP.

Some Helpful Terms:

-Autotrophs: Organisms that make their own food, sustaining themselves
-Producers: Organisms that make up the food supply
-Photoautotrophs: Organisms that produce organic materials from inorganic molecules using light energy
-Chlorophyll: Light-absorbing pigment in chloroplasts that converts solar energy into chemical energy
-Mesophyll: The green tissue in the interior of the leaf where chloroplasts are concentrated
-Stomata: Pores in the lead in which CO2 enters
-Stroma: Thick fluid inside the chloroplasts
-Thylakoids: Sacks suspended in in the stroma
-Grana: Stacks of thylakoids
-Photosystem: A light-center complex consisting of light-harvesting complexes.

Diagram:

The plant that contains chlorophyll is absorbing the light energy from the sun. Not only that, but it also takes in the CO2. Within the plant, photosynthesis occurs, releasing oxygen and creating glucose.














Summary:
This chapter was about photosynthesis, which is another way that cells harvest energy, but this is exclusively to plants and other organisms that contain chloroplasts and chlorophyll. Plants are known as the producers, as they create their own food, and consumers eat them for their energy.
Photosynthesis consumes sunlight and water and produces O2 and carbohydrates for the plant. There are two types of energy cycles for plants- one is the light cycle (photosynthesis) and the dark cycle (the calvin cycle).


A Cool Video:
http://www.youtube.com/watch?v=C1_uez5WX1o

The Cellular Basis of Reproduction and Inheritance

What are the stages of cell reproduction?

1) Interphase
2) Prophase
3) Metaphase
4) Anaphase
5) Telophase
6) Cytokinesis

What is Mitosis? 

Cell reproduction consisting of one cell dividing it's genetic information into two identical cells, barring mutation.

What are the differences between animal and plant mitosis?


Animal cells, since they don't have a cell wall, have a cleavage furrow right as they're about to split, that will become part of the new cell membranes. In plants, since they have a cell wall, they develop a cell plate in between them that will become the new part of the cell wall. Not only that, but plants also have to split up their chloroplasts, something animals do not have.

The Facts:

-Sexual reproduction allows for quick adaptation and evolution
-Asexual reproduction usually creates identical offspring to the parent, but cannot adapt very fast
-Prokaryotes reproduce mostly by binary fission
-Because of anchorage dependence, if you left some animal cells in a dish, they'd grow along the bottom
-A tumor is uncontrolled growth of cells
-A benign tumor is one that stays on it's origin
-A malignant tumor is one that spreads to other tissues
-Haploid gametes are created by splitting sex cells into halves, each with half the genetic information
-Meiosis consists of two cycles of splitting, ending in four cells as opposed to two
-There are many genetic disorders caused by failures in chromosome development.

Some Helpful Terms:

-Asexual Reproduction: The creation of genetically identical offspring by a single parent without the presence of sperm or an egg
-Chromosomes: Structures that contain most of the organism's DNA
-Binary Fission: Prokaryotes use this type of reproduction, essentially just splitting themselves in half.
-Chromatin: A combination of DNA and protein molecules
-Sister Chromatids: Identical copies of a DNA molecule
-Centromere: What joins the chromatids together
-Interphase: Takes up most of the cell's life, this is while it is performing it's normal functions
-Density-Dependent Inhibition: A phenomenon in which crowded cells don't divide.
-Anchorage Dependence: When cells have to be in contact with a solid surface to divide.
-Metastasis: The spread of cancer cells beyond their origin

Diagram: 

(Going clockwise)
Interphase cell: Performing intended functions
Prophase: Nuclear envelope dissolved, chromosomes free
Metaphase: Chromosomes lining up, spindles attaching
Anaphase: Cell is beginning to split, chromosomes split apart, going to different sides
Telophase: Cells almost completely divided, nuclear envelope reforms on both sides










Summary:
This chapter covers cell reproduction, both mitosis and meiosis. Mitosis is the asexual reproduction of cells, whereas meiosis is specifically for the sex cells. Asexual reproduction requires no mate, and produces genetically similar offspring. In animals, sexual reproduction requires a mate, but produces genetically varied offspring, and is very susceptible to adaptation.
This also gives some good real-life examples of when things go wrong- tumors are uncontrolled cell growth. While from a perspective of cell reproduction, interphase seems rather useless, in fact that's a very good thing, seeing as that is when the cell is doing its job.


A Cool Video:

(warning, contains profanity)
http://www.youtube.com/watch?v=cxNNOcVOwaU

How Cells Harvest Chemical Energy

What is the equation for cellular respiration?

C6H12O6 + 6O2 --> 6CO2 + 6H2O + ATPs (Energy)

What are the three stages of Cellular Respiration?

Stage 1: Glycolysis
Stage 2: The citric acid cycle
Stage 3: Oxidative phosphorylation

Where do the three stages take place?

Glycolysis: Cytoplasm
Citric Acid Cycle: Inside the Mitochondria
Oxidative Phosphorylation: Inner mitochondrial membrane

The Facts:

- Slow-twitch muscles are better for endurance running; they can sustain repeated use, but don't provide lots of speed
- Fast-twich muscles are better for sprinting; they fatigue quickly, but provide lots of speed
- Almost all eukaryotic cells go through cellular respiration
- Glycolysis breaks down glucose into two pyruvate
- Pyruvate is a three-carbon compound used in cellular respiration
- The Citric Acid Cycle breaks down the pyruvate and creates Carbon Dioxide, the main purpose is to supply oxidative phosphorylation with electrons
- Oxidative Phosphorylation deals with the electron chain and chemiosmosis
- Chemiosmosis uses the concentration gradient's potential energy to create ATP
- Fermentation is a type of respiration that doesn't require oxygen
- Certain poisons block the electron transport chain, others inhibit ATP synthase

Some Helpful Terms:

-Redox reaction: The movement from one molecule to another
-Oxidation: Loss of electrons from one substance
-Reduction: Gaining electrons to one substance
-Electron Transport Chain: Serious of redox reactions in which electrons pass in steps to oxygen
-Substrate-Level Phosporylation: An enzyme transfer from a phosphate group, forming ADP to ATP
-Chemiosmosis: Chemical osmosis through the concentration gradient, energy produced used to make ATP
-Lactic Acid Fermentation: Used to regenerate NAD+, converted into pyruvate
-Alcohol Fermentation: Yeast in anaerobic enviroments converts pyruvate to CO2 and ethanol
-Obligate Anaerobes: Organisms that are poisoned by oxygen
-Facultative Anaerobes: Can make ATP with either fermentation or oxidative phosphorylation

Diagram:

Glucose starts off as the energy source. It goes through glycolysis to prepare to become pyruvate, generating 2 ATP molecules just by itself. Then the pyruvate becomes the energy source for either aerobic or anaerobic respiration, the latter going through fermentation, producing Lactic acid or Ethanol. The former that uses oxygen, the pyruvate goes through the Krebs (Citric Acid) cycle, producing CO2 and sent to the electron transport chain, taking in oxygen, producing H2O and some ATP










Summary:
This chapter was very specifically about cell respiration and how the cells make energy (ATP). Basically it goes through the steps of cell respiration- Glycolysis, which prepares the glucose for the citric acid cycle, by making most of it into pyruvate and producing 2 ATP. During the citric acid cycle, oxygen is used to finish creating pyruvate and sending it to the electron transport chain.
Then during oxidative phosphorylation, water is produced, as well as 34-36 ATPs. This produces the most energy. Then fermentation is the cycle of respiration that requires no oxygen, and produces lactic acid and ehtanol.

Cool Video:
 http://www.youtube.com/watch?v=vlZZUtpyCgQ