Biology H Midterm

Unit 1: Why is change a friend or foe?

Frozen frog case study

• Once the frog touches the ice crystal it begins to freeze.

• After it touches the crystal a signal is set off in the frog that pulls water from the center of its body.

• The organs are now wrapped in a puddle of water that turns to ice.

• There is no breathing, kidney function, and the heart stops beating.

• Lasts from days to weeks

• The frogs blood sugar is distributed though the circulatory system which works like an anti-freeze (It gets circulated throughout your engine by the water pump, which allows it to bring combustion-generated heat away from your engine.)

• Cells stay just damp enough for the frog to hold itself together/alive

• Frog defreezes/comes to life during the spring again

• Produces urine and stores it in its blood, then it freezes.

• Liver begins to make glucose which mixes with the urine, which creates homemade anti-freeze

• this antifreeze prevents too much water being drawn out of the cells by the ice outside

Selective Pressure: some type of “force” present in the environment that conveys/reveals certain atributes to be positive or negative to an organism.

Genetic Trait: A specific characteristic of an individual.

Mutation: a random occurance

• Take place within an organism DNA and may or may not be passed onto the next generation

• Must be in reproductive cell/gametes to be passed on

• Change in nucleic acid

• RNA+DNA are both types of nucleic acids

• When A + T or C + G don’t match up

• Something could go wrong during DNA replication (interphase - stage that prepares cells to divide during mitosis)

• Most mutations are neutral

• Other genes in the body can influence whether genes will be turned on or turned off

Sickle Cell Anemia

• Hemoglobin is a protein in red blood cells that help to carry oxygen

• With the disorder the gene that codes for hemoglobin is mutated.

• If you inherit two copied of this mutated gene, you can have the disorder

• Makes it difficult for red blood cells to carry oxygen because the shape of the red blood cell is affected from the mutated hemoglobin protein. Can lead to anemia and other issues.

• If you only inherit one copy of the mutated gene you are a carrier of it but you don’t actually have the disease, don’t even have symptoms

• But oddly carriers have a protective factor against malaria

• Malaria: a disease caused by a protist (an organism) that can be transmitted by mosquitos

• These people can get malaria but their symptoms are less severe

• In this case one copy of this mutation can be an advantage if you live in an area where malaria is present (beneficial)

  Video #2

• blood cells become misshapen, crescents instead of disks

• Preventing enough oxygen from being delivered to all parts of the body

• Fairly common disease

• Most people had it lived on the coat near water where malaria carrying mosquitoes lived

• genes are lined up on the chromosomes and one has pairs of them (exception of sex cells) this means there are two copies, these can be the same (homozygous) or different (heterozygous) than each other.

Gene mutations

• DNA makes up genes, the genes code for protein that influence/make up other traits

• When DNA changes (mutated) different proteins can be produced which affects the traits

• Subtitution: Wrong base matched (ex. A+C or G+T)

• Insertion: Extra base or bases are added in

• Deletion: Base is missing/removed

• Insertion and deletion are especially dangerous because it messed up the reading of the code which means everything after the mutation is messed up (frameshift)

Chromosome mutations

• Chromosomes are made of of DNA and protein, are highly organized with lots of genes on them

• Everybody cell in the body have 46 chromosomes in them

• Human sperm + egg cells have 23 chromosomes in them

• Duplication: (in chromosomes) extra copies of gene and chromosome generated

• Deletion: Some genetic material from chromosome breaks off

• Inversion: Broken chromosome segment gets reversed (swapped) and put back on chromosome and attaches to another chromosome

• Translocation: Fragment of one chromosome breaks off and attaches to another chromosome

Nondisjunction: When chromosomes seperate during meiosis, they are not seperating completely. Results in an egg or sperm that has too many or too few chromosomes. Can cause a genetic disorder depending on which chromosome. Each chromosomes contain different genes so depending on which pair is effected makes a difference.

Beneficial trait: Potential advantage has a positive impact on the organism.

Nuetral trait: Doesn’t impact an organisms ability to function or reproduce (silent)

Detrimental trait: Potential disadvantage, has a negative impact on the organism.

Antibiotic resistance Formal lab

Lawn of Bacteria: The appearance of bacterial colonies when all the individual colonies on a Petri dish or agar plate merge to form a field or mat of bacteria.

Susceptable: The antibiotic stopped the growth or killed the bacteria.

Intermediate: The antibiotic may work at a higher dose, but overall doesn’t work very well

Resistant: Bacteria changes so that the antibiotic medicines can’t kill them or stop their growth.

How antibiotics affect bacteria?

• Antibiotics are capable of evolving resistance to extremely high concentrations in a short period of time.

• Selection of resistant bacteria by the use of antibiotics which leaves only the resistant bacteria to reproduce and pass on their antibiotic resistance genes. The susceptible bacteria are killed so not prevented from pass on their genes.

• Antibiotics kill the majority of susceptible bacteria fairly quickly

• A bacterium is made up of thousand of complex processes inside to keep them alive, the antibiotics disrupt this complex machinery (ex. interfering with its metaboliism, to slow down there growth, and they are less of a threat.

• Some antibiotics attack DNA and prevent it from being replicated, which stops bacteria from multiplying, ultimately killing them.

• This all happens without bothering the body cells

• Some bacteria evolve in a way to protect themeselves, they can intercept the antibiotics and changing the molecule so it becomes harmless

• Others invest energy in pumps that eject the antibiotics before they can do damage

• A few immune bacteria are not a big of a deal because the immune system can take care of them but if they escape they can spread the immunity

• Bacteria has two types of DNA: Chromosomes + plasmids

• The bacteria can transfer plasmid to eachother to exchange useful abilities

• Or bacteria can harvest dead bacteria and ollect DNA pieces

• This can happen between different kinds of bacteria and can cause bacterias to be immune to different kinds of antibiotics (superbugs)

• Hospitals are the perfect breeding grounds for these superbugs

• By treating so many organisms with antibiotics we are creating more superbugs that are resistant, then we begin using different antibiotics

• There are certain antibiotics that are used to wipe out bacteria that have developed resistance

• When bacteria is found in the body white blood cells are signaled to rid of them but sometimes there are too much bacteria for the white blood cells to rid of

• At this point antibiotics are needed to help

• Before bacterial cells divide they duplicate their genetic material, which is composed of DNA (holds precise information on the activity and development of the bacteria)

• Mutation for resistance against antibiotics occurs, that bacteria multiplies quickly

Environmental pressure of antibiotics

• Temperature and population density

Unit 2: How are outcomes determined by reaction(s) to the changing environment?

Selection drives evolution

Anole Lizard

• All the anoles mostly eats spiders and crickets

• Each type lives in a different habitat

• A long tailed slender species lives in grasses and bushes (grass-bush anole)

• On low parts of tree trunks and on the ground a longer legged stocker species lives (trunk-ground anole)

• Higher up the tree lives larger anole with toe pads (canopy-anole)

• On very small twigs anoles are found with short legs (twig anole)

• The fact that lizards differ in leg length and toe pad size depending on where they live suggests that these differences in traits are adaptations to the lizards habitats

• trunk-ground anole can sprint

• twig anole with short legs cant sprint

• twig anole can move comfortably on a thin branch

• trunk-ground anole can hardly hang on to the thin branch

• trunk-ground lizard falls right off the large leaf

• canopy anole easily climb up leaf

• On each of the 7 islands they placed a male and female anole

• The island only have small bushes and no trees

• They came back a year later and they had reproduced

• The new population had grown and is living on thin branches, they recorded information and put them back in the exact spot

• They came back another year later and the average lizard leg had shortened in just two generations

• Evolution can happen very rapidly when natural selection is strong

• Two groups of animals are considered different species when individuals from one group don’t reproduce with the other, so something has to be preventing the lizards from breeding with closely related populations

• Reproductive Isolation: Over time, members of two populations stop inbreeding, changes in one gene pool can not spread to the other.

• One way for a species to split into two is for populations to separate geographically

• Over many generations they can undergo enough changes in their habitats that when they come back together again they don’t mate.

• Anoles have a flap of skin under their throats (dewlap) which males use to attract females

• Every species in the same area has a different dewlap.

• grass-bush anole lives in a dark environment and has a bright dewlap. Anoles in a lighter habitat have dark dewlaps

• The dewlap must contrast its environment to stand out

• If two different anole species with different dewlaps come together the female will not recognize the male as a member of the same species so they do not mate.

• Once the new species has formed competition drives the evolution of different body types

• Species living in the same area compete for resources, but if they find another habitat they can use resources not available to the other species

• Each nearby islands all have the same four body types of anoles

• The lizards on each island tend to be more closely related to each other than to similiar looking lizards on different island. This means that the same type of lizards evolved independently on each island

Variation in traits

• Variation in traits is beneficial because this leads to some organisms having beneficial traits

• This intern leads to this trait moving on and evolution to help the survival of an organism

• But some traits may not have a benefit based on surroundings, the traits can be neutral or detrimental

• Does not ensure survival.

• If there is a population with no variation in traits, a change in the environment will easily kill off the entire population

Meiosis Ensures Variation

• Homologous chromosome pairs trade segments with the other chromosome at random locations

• Replicate: Tetrad is formed by four chromatids

• Variation: Original homologous pair cross-over exchanging equal section with each other

• Reduce chromosome #: Homologous chromosomes are split apart into sister chromatid pairs

• Diploid cell: has two complete sets of chromosomes

• Haploid cell: Cell that contains a single cell of chromosomes

• Recombination during meiosis results in the combination of maternal and paternal alleles onto the same chromosome, causing shuffling of alleles.

Allele: One of two or more versions of a genetic sequence at a particular region on a chromosome.

Phenotype: The observable characteristics or traits in an individual based on the expression of their genes.

Genotype: A term that refers to the two alleles present at a specific locus in the genome.

Homozygous: When you inherit the same DNA sequence for a specific gene from each of your biological parents.

Heterozygous: A term that describes having two different versions of the same gene

Genotypic ratio: Describes the number of times a genotype would appear in the offspring after a test cross.

Phenotypic ratio: A ratio comparing the possible outcomes for an organism based on physical appearance.

Punnet squares: A square diagram that is composed of a grid of usually four boxes and is used to calculate and depict all the combinations and frequencies of the different genotypes and phenotypes among the offspring

Dominant: A trait that will appear in the offspring if one of the parents contributes it.

Recessive: A gene that can be masked by a dominant gene.

Evidence for evolution

Embryology

• When organisms are fetus’s it is easy to see the similairities and prove how there is a common ancestors between all of them

• Dolphin and Human embryos both have arm and leg buds.

• The dolphins early fetus have nostrils just as a human or puppy would.

Vesigal structures

• Homologous structures that dont serve important functions

• Mammals have legs but whales do not, but they do have a strange combination of bones that look like a shriveled hip, thigh and shin bones. Along with a ball and socket joint.

Analohous structues

• Body parts that serve similair functions, but do not share structure and development

Homologous structures

• Similiar structures, like the bones of vertebrate limbs that are shared by related species and have been inherited from a common ancestor

• Both whales and mammals have placentas, give live birth, feed milk to their young, they are warm-blooded (extremely rare for fish), do not have gills, breathe air with lungs, have hair, arm, wrist, hand, finger bones

DNA + amino acid relationship: the DNA sequence of a gene determines the amino acid sequence for the protein it encodes.

Fossil record: Made up of all the fossils that have been found, along with their relative ages. Scientists can look at patterns in the fossil record to understand the history of life on Earth.

Octopus

What do the behaviors of the octopus allow them to do?

When a predator creeps up on an octupus it is able to scurry away on two of their tentacles

How would these relate to survival?

When the octpi use their jet power to move it actually stops their heart which is unsafe but if they walk on two than can go fast enough without their heart stopping

Lastly, how can behaviors be related to evolution?

These behaviors are controlled by genes and may evolve through natural section

Unit 3: Science Our Savior or Demise

DNA structure

Chromatid: supercoiled DNA present during interphase

The two “sister” chromatids are joined at a constricted region of the chromosome called the centromere. During cell division, spindle fibers attach to the centromere and pull each of the sister chromatids to opposite sides of the cell. Soon after, the cell divides in two, resulting in daughter cells with identical DNA.

Nucleotides:

A molecule that is the basic building block of the nucleic acids DNA and RNA. A nucleotide is made up of a nitrogen-containing base (adenine, guanine, thymine, and cytosine(four bases of DNA)) in DNA

Complementary base pairing: C=G A=T

DNA Shape (Double Helix): DNA's unique structure enables the molecule to copy itself during cell division. When a cell prepares to divide, the DNA helix splits down the middle and becomes two single strands. These single strands serve as templates for building two new, double-stranded DNA molecules - each a replica of the original DNA molecule.

Selective Breeding

• Benefits: To get desired traits in organisms that can improve living like breeding plants that we eat or making animals less harmful

• Cons: Can cause health issues in organisms, it takes a long time, mutations can occur, small gene pool, inbreeding

• Purpose: Breeding two animals together to get another organism with a desired trait

DNA editing

• GMO: a plant, animal or microbe in which one or more changes have been made to the genome, typically using high-tech genetic engineering, in an attempt to alter the characteristics of an organism

• GMO: Stands for a genetically modified organism, the genes inside the organism are modified.

• Recombinant plasmid: a foreign DNA fragment is inserted into a plasmid vector (envelope).

• Sticky ends: overhangs of single-stranded DNA molecules after being cut with a restriction enzyme

• Restriction Enzymes: a DNA-cutting enzyme that recognizes specific sites in DNA

• Ligase/DNA scissors

Glowing gene lab

1. The ara (arabinose:fingers) turn on the ara C(switch) on

2. Signals the RNA Pol to attach to the ara C

3. Reads the Glowing gene and sends proteins to make flouresence