Section 2

Plasma Membranes

-              Plasma Membrane – all cells have a plasma membrane. They’re made of hydrophilic ends and hydrophobic trail lipids. This lipid shape creates important properties!

o  Double layer of molecules letting all of the insides stay in and hold water and giving it flexibility to be semipermeable.

o  Semipermeable = allows some things to pass through

-              Solute – molecules dissolved in the liquid.

-              Solvent – liquid that dissolves the molecule.

-              Concentration Gradient = solutes always move away from areas of high solutes to where there’s less or none. Membranes cause this (few in and a lot out or lots in and a few out).

Cellular Transport

-              A lot of functions are results of moving in things in and out of the cell -> membranes allow some molecules to easily pass through while others need an energy boost.

-              Two types! Passive = Osmosis and diffusion!

-              Diffusion – moves particles dissolved in gas or liquids from high to low concentration. Cells can do/let this happen naturally but some also need transport proteins if the molecules are too large or slow moving.

-              Osmosis – moves water across the cell membrane based on tonicity, the amount of solutes inside verses outside the cell, water wants to go to where there’s more solutes so it can dissolve the solutes.

-              3 Levels of Tonicity – Hypo (overflow of cells), Iso (equal nothing happens), and Hyper (water rushes out of the cell). All based on amount of solutes outside the cell.

-              Because of vacuoles plants tend to be more tonicity tolerant. Cell walls also help prevent issues too.

Mitosis/Meiosis/Division.

-              Mitosis = how cells divide and grow. DNA is copied and the cell is split in half once and each new cell gets a full duplicate of DNA. Has 6 main steps.

o  Interphase – most of the cells lifetime doing it’s regular thing

o  Prophase – cells start to prep by duplicating DNA which is packed to be moved easier

o  Metaphase – DNA lines up and moves to the center of the cell

o  Anaphase – Middle arranged DNA is pulled apart to opposite sides of the cell

o  Telophase – The second cell’s structures begin to form and the double DNA is unpacked.

o  Cytokinesis- The “almost” cells are split into two separate cells and mitosis ends.

Types of New Cells

-              Somatic – regular cells and full copies and the result of mitosis. Majority of the organisms cells if not all of them.

-              Reproductive – from Meiosis and are sex cells and have varying half’s of DNA.

Meiosis!

-              Meiosis - Occurs when organisms sexually reproduce, normal cells becomes a sperm or egg cell, during Meiosis all DNA is split in half twice.

o  Metaphase happens twice. This splits the DNA copy into halves because only one copy is ever made. This creates 4 cells including the now quartered bit of DNA from the mother cell!

o  Meiosis outcome is 4 haploid cells! Each have 1 set of chromosomes to not only create variation in population but to also help when combined with another gamete sex cell!

o  Guys start around puberty and never really stop. Women start with a set amount they create in the womb that slowly die off. For both there’s usually periods of pauses and resumes.

Chapter 6

Genetics!

-              Nucleic Acids store information and “spell proteins correctly. Have DNA and RNA.

-              DNA – Stores information for later uses, made of Adenine and Thymine, as well as Guanine and Cytosine. Hydrogen bonds hold DNA base pairs together!

o  Adenine always bonds with Thymine and Guanine always bonds with Cytosine. These pairs are called compliments. * replace T with U in RNA.

-              Mitosis has 6 main steps – prophase is when DNA copies are prepared for the second cell! This is important!

-              DNA replication…happens so easily because it has only 2 strands. To copy the DNA the hydrogen bonds are broken then the hives aer complimented with new copies! Semi-conservative because some of the old is left behind while the new is there as well!

o  Spot Check. Pair to GAATTC? = CTTAAG = C

-              Genome – All your genomes are stored in chromosomes in your chromosomes in the nucleus. A genome is all of the DNA letters in your body, in a specific order.

o  A gene is a small segment of those DNA chains! Not the whole genome!

o  A chromosome is a large molecule holding and organizing genomes to keep safe! Thus, chromosomes are where genes are located.

o  Humans have 23 pairs from each parent leading to 46 all together.

§  Genomes look like long, long strings of nucleotide letters.

-              While most humans have the same genes we all have different alleles. Alleles are like the same words            but different ways of pronouncing them

o  Basically… a chromosome is a collection of DNA that have genes, a gene is a specific nucleotide sequence, and an allele is a slightly alternative version of of a gene.

o  Genes in a chromosome are located in a Locus! Helpful when locating genes in a specific chromosome spot.

DNA Replication Errors!

-              Cancer occurs when some disruption of the DNA in a normal cell interferes with the cell’s ability to regulate cell division. Can be caused by chemicals, high energy sources, radiation, even some viruses. Once it loses control of cell division it loses it for good and goes on unrestrained. It also divides indefinitely unlike normal cells which have limits. They also lose “stickiness” and instead of staying together they tend to wander.

-              Benign. – Masses of normal cells that don’t spread

-              Malignant – They are cancerous and growing continuously while shedding cells. This links to metastasis where they spread and grow causing more tumors.

-              Most times… cells find and catch these mess ups, but cancer is when this gets out of control.

-              The danger is when that clump of cells/tumor gets too big or hurts or encroaches on helpful/healthy cells.

-              Chemotherapy and radiation – works by slowing down the cell division process

Chapter 7

Inheritance (Chromosomes)

-              Meiosis allows genetic variation

-              However…

o  only half of our alleles are passed on meaning some really good ones still miss out.

o   It also takes a lot of time and energy to find a partner.  It also can put dangers in the way in order to mate.

o   Mistakes and chromosomal disorders also occur.

-              Asexual reproduction avoids this by breaking off parts (starfish and plants) and forming whole organisms from that.

o  All alleles are passed on during this.

o  Faster and low energy

o  Less risky

-              But…

o  Advantages inverse and so do disadvantages.

-              In humans… there are 23 pairs of chromosomes in every somatic cells. 22 of them aren’t going to affect the sex of a person, one pair however does. XY = male. XX = female.

o  Male determines sex because… only the male carries the Y’s so it’s them who creates the variation!

-              For non humans – Hermaphrodites, can make both male and female gametes.

-              Karyotype – A display of an individuals complete set of chromosomes.

-              Chromosomal Deviation – Causes some issues…

Chromosomal Issues

-              Nondisjunction – Unequal distribution of chromosomes during meiosis. Can cause cells that have 2 or 0 of a specific chromosome.

-              This can lead too… Down syndrome, XXY/Klinefelter syndrome, XXX/meta females, Turner syndrome/X, and XYY/super males. (Those tend to lead to developmental issues or height issues and sterile issues.) Also issues if there’s less of a chromosome (Turner as well).

(Inheritance) Traits/Genes

-              Some traits are controlled by a single gene or by multiple genes.

o  Heredity – the passing of characteristics from parent to offspring.

-              Single Gene traits – Ex. Fur length in cats and coat color in cats.

-              Mendels Research Approach – Garden plants and cross breeding.

o  A dominant trait masks the effect of a recessive trait.

o  Usually Dominant = uppercase, recessive = lowercase. Ex – Purple and white

-              Phenotype – The observable traits expressed by an organism.

-              Genotype – An organisms underlying genetic makeup consisting of the physically visible and the non expressed alleles.

o  Will be expressed as – Two Uppercase, one Upper and one lower, or both lower.

o  Homozygous – same letters/traits

o  Heterozygous – different traits but the dominant still takes over

-              Punnet Square – used to figure out what the likeliness of a geno and phenotype wold be. Can be real big or real tiny.

-              Probability and Chance – play central roles in genetics

-              Probabilities – if a male heterozygous for albinism (Mn) and a female homozygous for it (mm) what is the probability that their child will be homozygous for al.

-              50% ^

-              Complete Dominance – when one allele completely dominates the other

-              Incomplete Dominance – heterozygote appears to be intermediate between the two homozygotes. (Red + white = pink)

-              Codominance – the heterozygotes display characteristics of both parents (spotted flowers)

Chapter 9&10

Blood Type

-              Different Antigens – How acceptors and donors are determined

o  Type A: Has A antigens in red blood cells, individual also produces antibodies that attack B antigens. Can donate to A and AB and accept from A and O

o  Type B: Have B antigens in the blood cells and produce A antigen attacking antibodies. Can donate to B and AB and accept B and O.

o  Type AB: Have both A and B antigens. A universal recipient as they produce neither A or B antibodies. Can only donate to AB.

o  The O: Has neither A or B antibodies but produces A and B antigens. A universal donor. Can only take in Type O bloood.

Gene Expression/Molecular Biology

-              Multiple Allelism - when a single gene has more than two alleles, each individual still only carries one allele

-              Genes Create Used Proteins - the point of a gene Is to create proteins that bodies have other uses for.

-              RNA - RNA is made up of four “base pairs” with one difference of Uracil rather than Thymine.

o  DNA = GAATTC to RNA = CUUAAG

-              Central Dogma – the fact that information in biology moves from DNA to RNA then to proteins. DNA to RNA is easy, RNA to DNA can be trickier.

-              Transcription – process where letters of DNA are copied into RNA

-              Translation – The process where letters of RNA are turned into Protein

-              Not all genes are turned on at one time! – If two cells have difference amounts and kinds or proteins then they are different cells. This is how your body can have hair, liver, skin, brain and heart cells while all having the same DNA inside them

-              Gene Expression – How much protein is made from a gene This is extremely complex, malfunctions in this process are detrimental to the cell and can lead to the development of many diseases and cancers.

-              Gene Regulation – Whether a gene is turned on or off.

Biotech

-              Biotechnology – Genetic engineering is one of it’s cornerstone.

o  Genetic Engineering – The corner stone of biotechnology! Since the mid 1980s scientists have been able to use special proteins to make Lots of DNA.

o  DNA Double Helix in electron microscope! DNA is incredibly small!

-              PCR – a laboratory technique used to make large amounts of workable DNA. Polymerase Chain Reaction. Mixes a sample of DNA with the protein polymerase and other ingredients into a special PCR machine for more DNA.

o  PCR – Heats DNA to break apart hydrogen bonds and then copies it a hundred times! Denaturing breaks it apart so the other ingredients can copy that DNA. Hundreds of times over! Just like during Mitosis.

§  Next you can look at the DNA you’ve made with special dyes!

-              WHY?? - This is used to mostly test for diseases in DNA. (Ex: Covid tests)

-              PCR vs Antigen (rapid) Tests – PCR is more lengthy in time but extremely accurate! Rapids are less time consuming but they can be less accurate and more influenced by other viruses.

o  Example 1: Three have covid, they each have parts of covid DNA even if faint.

o  Example 2: Sample 1 has zero covid DNA.

-              Other PCR Uses – Genetic testing, personal DNA tests, genetic mapping (human genome project). Forensic testing (even just fingerprints)

Recombinant DNA

-              Genetic Engineering - Recombinant DNA – Once you’ve made several DNAs you can take it and add it to different DNA. Ex: taking human insulin DNA and insert into bacterial loop of DNA. Then multiply like crazy and make insulin.

-              Using Recombinant DNA – (DNA fragments generated from PCR or other methods) To get an organism to do what you want.

-              Transgenic – An organism with DNA from another species.

-              GMOS – Genetically modified organisms have lots of advantages. Not always transgenic! (Human to human but not transgenic!) Can be made with both.

o  Pros : Can be used to help resist diseases both in plants and animals like mosquitos. (Mosquito that has 2 extra genes to help them glow and resist malaria)

o  Cons: While GMO crops are safe to eat, the use of these crops is associated with more herbicide uses (roundup-ready corn causes more sprayed roundup)

Biotech Pt 2

-              Biotechnology – the alteration of organisms, cells, and their molecules to achieve some practical outcome.

-              Genetic Engineering – adding, deleting, or transplanting genes from one organism to another, to alter the organisms in useful ways.

-              Tools: While there are many uses there are a small number of tools used in the process.

o  Chop up DNA from a donor species, Amplify small samples of DNA into more useful quantities, then Insert pieces of DNA into bacterial cells or viruses, Grow separate colonies of bacteria or viruses with each containing some donor DNA, finally Identify colonies of bacteria or viruses that have DNA for a trait of interest. (Think INSULIN!)

-              Early Genetic Engineering: Selective breeding was early agricultural biotechnology. Ex -> dog breeding for herding, hunting, and looks.

GMOs

-              Almost everyone in the U.S. consumes genetically modified crops regularly without knowing it. GMOs! Mostly – corn, cotton, soybeans.

-              Why do it? (Pros) –

o  Make more nutritious food like engineered golden rice to combat vitamin deficiency in children.

o  Feed more people! Better food growth!

o  Faster growth and bigger bodies

o  Insect resistance in crops to avoid losses in crop output.

o  Herbicide resistance in crops.

-              Why not? (Cons) –

o  are safe to eat but can lead to more herbicide use on crops

o  Environmental issues when bigger growth leads to more consumed resources and be too large to be consumed by natural predators!

-              Fears and Risks?

o  Safe? Are they safe is a concern but they do undergo the same food and safety regulations and testing as all other foods in the US.

o  But…

§  Organisms that we want to kill may become unkillable

§  Organisms that we don’t want to kill may be killed inadvertently.

§  GMO crops may not be tested or regulated adequately

§  Could become dangerous to consume

§  Loss of genetic diversity amount crop plants can be risky

§  Herbicides left on plants can be consumed!

o  Your Opinion: somewhat agree. I wish it was used more responsibly and studied for affects more.

-              Treatment of diseases and production of medicines – improved with biotechnology

o  Prevent diseases

o  Cure diseases

o  Treating diseases (insulin production!)

-              Also led to discovery of… Human growth hormones, and Erythropoietin (EPO) to treat anemia

Gene Therapy

-              If you carried a gene that meant you would develop a disease later in life would you want to know?

-              Would you want to know if there’s a chance your future children would be born with a genetic disease.

-              Gene Therapy: The technique used to cure heritable diseases by replacing mutant (undesireable) genes with good genes to prevent diseases.

o  Reduces disease causing proteins and increase working proteins or even produce new proteins.

o  Uncommon to be used and not easy

o  Difficult getting the working gene into specific cells where needed

-              Cloning? 1997 Dolly the Sheep was the first mammal cloned from the adult cell.

o  Are the medical (any?) justifications for cloning? Can a human be cloned and should they?