Bio Lab FInal
Mitosis Can be futher broken into down into five subphases: prophase, prometaphase, metaphase, anaphase, and telophase. The first four subphases are dedicaed to the division of the genetic material.
Prophaes is a subphase of mitosis. The DNA in the nucleus condenses into visible chromosomes, each composed of two chorotides that are held together at the centrome. The nuclear membrans that encloses and protects the chromosomes in the cell beings to disassemble.
Metaphase is a subphase of mitosis. The spindle apparatus forms at opposite sides of the cell. THe spindle apparatus is a colmplex composed of dynamix microtubule fibers that attach to the chromosomes and pushes and pulls them into a single stacked like (called the metaphase plate) tht is prependicular to the spindle acis
Anaphase is the next subphase of mitosis. After all of the choromosomes are aligned on the metaphase plate, each pair of sister chromoatids splits at the centromere, seperates, and moves along shortening spindle fibers to oppsite sides of the cell. Each separated chromosome has only one chromotide.
Telophase is a subphase of mitosis. Chromosomes, wach with one chromatide, arrive ar opposite poles of the cell, and a nucleus forms around each of the teo new sets of chromosomes. The spindle apparatus begins to disassemble and the chromosomes decondense.
Although the necleus and the chromosomes divide during mitosis, cytoplasm does not. following mitosis, cytokinseis is the process where the cytoplasm of a eukaryotic cell is divided to form two daughter cells.
In animals cells the center of the cells contracts like a belt around a waist, eventually pinching the cell into two daughter cells, each of which contains a nucleus with a complete genome
The rigid cell wall prevents this in plants cells, so a new plasma membrane is synthesized in the middle of the cell, dividing the sytoplasm into two seperate cells.
While a zygote and its daughter cells reproduce asecually to build all the cells that represent an organism, the actual zygote is nore created the same way; it is formed through sexual reporduction. Sexual Reproduction is a from of reproduction where two distinct types of specialized sex cells called gamets. These gametes fuse together (process known as fertitilization) combine their genetic content. The gamete produced by male animals is know as the sperm produced by females is the ovum (known as the egg)
The division of cells is solved through meiosis. Meiosis only occurs in a select population of cells called germ cells, and only germ cells can produce gametes. The germ cells in human males rest in the testes, while the germ cells in a human women are in the ovaries. The remaining cells in your body, the bulk of what you are, are call somatic cells. Somatic cells reproduce by mitosis, not meiosis.
Meiosis is a type of cell division that reduces the number of chromosomes in a cell by half. In human cells, this reduces the 46 chromosomes in a diploid cell to 23 chromosomes. It is critcal to note that these are not in a random assortment of any 23 chromosomes, but a collection of onw chromosomes of each of the homogous chromosomes pairs. The end result is a cell, the gamaets, which has one complete set of genetic information or haploid genome.
The same four subphases of mitosis are also seen in meiosis. However, cells undergoing meiosis will process through these subphases twice - the first passages through the subphases is meiosis I and the secon passage is called meiosis II. While there are important differences betwenn meiosis I and meiosis II, the cellular processes are similar in what occurs:
Prophase The DNA in the nucleus begins to condense and becomes visible as chromosomes, each composed of two chromostides that are held together at the centromer. The nuclear membrane that encloses and ortects the chromosomes in the cell begins to disassemble
Metaphase The spindle apparatus froms at opposite sides of the cell. The spindle apparatus is a complex composed of dynamic microtuble fibers that attach to the chromosomes and pushes and pulls them into a single stacked line ( Called metaphase plate) that is perpendicularto the spindle axis.
Anaphase After all of the choromosomes are aligned on the metaphases plate, each pair of sister chromotides splits at the centomere, seperates, and moves along the shortening spindle fibers fibers to opposite sides of the cell. Each seperated chromosome has only one chromoatid.
Telophase: Chromosomes, each with one chromatid arrive at opposite poles of the cell, and a new nucleus forms around each two new sets of chromosomes. The spindle apparatus begins to dissassemble and the chromosomes decondense.
Another result of meiosis result of meiosus is genetically diversified population of gametes. Eash parent cell contains two of each chromosome, and which of these chromosomes ends up in each gamete is comletely random. Consider that analogy of shuffling a deck of cards; each suit, 2 through 10 plus a, J, Q, K. Now scramble the two sets together and randomly serparate them into two sets that each contain one of each card. How many possible combinations could you come up with? The seperation of chromosomes during meiosis undergo similar scrambling resulting in gametes that contain a complete yet random set of chromosomes.
Most eukaryotic cells contain two complete sets of chromosomes, with one set originating from the father and the other from the mother. Two complete sets consitute a diploid genome. Diploids cells containd four chromosomes. Each chromosome contributed by the father had a corresponding chromosome that was contributed by the mother. The corresponding chromsomes which are alike in structure and size, constitute a homologous pair. The genetic content of homologous chromosomes is very similar but not identical.
Every human diploid cell contains 23 pairs of chromosomes: one chromosome from eah pair is inerited from the father, via sperm, nd the other is inherited from the mother, via the egg, Note that 22 of the are autosomes ( homologous pairs of autosomes 1 through 22) and one pair is sex chromosomes. This 23 pair of sex chromosomes in humand dertermines sex an XX pair produces females, while an XY pair produces males. Somtimes diploid chromosomes numer is described as 2n, with n being the equivalent of a haploid ( half of diploid) genome. For humans 2n equals 46 and n equals 23.
Genotype is the combination of alleles for every gene in organisms genome. While phenotypes are physical properties and traits of cells and organisms.
A Punnett square is a graphical representation used in genetics to predict the genetic makeup of offspring resulting from a cross between two individuals. It helps visualize the possible allele combinations and their probabilities:
Structure: The square is divided into sections, with each row representing the alleles from one parent and each column representing the alleles from the other parent.
Purpose: It allows for easy calculation of genotypes (allele combinations) and phenotypes (observable traits) of the offspring.
Example: If we cross a homozygous dominant plant (AA) with a homozygous recessive plant (aa), the Punnett square would have 4 boxes, all showing Aa, indicating that all offspring will be heterozygous and display the dominant trait.
Utility: Useful in predicting traits and studying genetic inheritance patterns, it helps understand inheritance in a simple and accessible way.
Popsicle stick exercise: Start by organizing chromosomes into colors. Prior to mitosis each chromosome must be replicated. THis takes the place during the S phase portion of the cell cycle. Model the replication by completing the following. For each of your 12 chromosomes select a matching popsicle stick precisely! once replicated there are no extra copies lying around in the cell. Following replication each chromosomeis composed of two identicle sister chromatides held together at a structure called a centromere. ALign the popsicle sricks sis by side to represent this attachment. You should end up with 12 chromosomes. After interphase the cells move into M-phase and the subphases of mitosis: prohase The chromosomes condense. metaphase the chtomsomes pairs alughn in the center of the cell along an invisible plince called the netaphase plate. Arrange chromosomes in a line from the top to the bottom. anaphase, the sister chromatids of each chromosomes pairs are pulled to opposite sides of the cell by the mitotic spindle apparatus. Model this by, place one sister chromatid on one side of the bench and the chromatid on the other side. Telpphase, Once the homologous chromosomes pairs have been seperated, a nucleus reforms around each set of chromosomes.
Gregor Mendel, the founder of classical genetics, dertermined the nature of genes (eventhough the role of DNA in ingeritance would not be revealed for another 50 years) while studying inheritance in pea plants. Through careful crossing (mating) of the plants, Mendel noticed that traits appeared in offspring in consistent ratios. Mendel used the term dominant to refer to a trait that appeared whenever an individual had the allele for that trait and receissieve to refer to a trait that only appeared when the gene for the dominant trait was absent. When he crossed his pea plants that were completely dominant against those that were completely recessive, he discovered, he discovered that all of the offspring diplated the dominant trait. When he crossed these individuals, he found that their offspring displayed a ration of three domminany for every one receessive (3:1). The result led him to conclude that individuals carry two copies of each gene and pass one copy of each gene to their offspring.
Homozygous is a term used to describe diploid genomes that have two of the same allele for a given gene. Heterozygous when the diploid has two different alleles for a given gene, resulting in a genotype that can express both dominant and recessive traits depending on the dominance relationship of the alleles.
Tools used to pull DNA from the Bannas and Straberries. These tools include a mortar, pestle, gauze, on top of a flask and gently push the gauze into the opening so it makes a small pouch. Carefully pour solution into a test tube add isopropanol into the graduated tube and insert the glass stirring rod to stir.
STR (DNA) profile, forensic investigators employ scientific methods and techinques to identify specific number of repeats present at each of the 13 CODIS STR locations for an individual. This profile can then be compared against a database to match DNA samples in criminal investigations to atleast prove the individual was in at the crime scene. STR’s are short tandem repeats are variable regions of a person’s genome, mostly between genes and therefore they do not affect the functioning of proteins, making them ideal markers for genetic identification and forensic analysis.
DNA Deoxyribonucleic Acid, is a polymer moecule which means it is made of smaller linked subunits ( may recall that proteins and carbohydrates are also polymer molecules) these subunits are called nucleotides. A nucleotide consists of three components
a phosphate group, a five-carbon sugar (deoxyribose in DNA), and a nitrogenous base, which can be one of four types: adenine, thymine, cytosine, or guanine.
The relationship between the partnered nitrogenous base pairs is complementary base pairing. These complementary bases are bonded together bia hydrogen bonds which can be eaily broken a part when the DNA need to accessed for duplication, Transcription, or repair.Nitrogenous bases are the building blocks of DNA, and there are four types: adenine (A), thymine (T), cytosine (C), and guanine (G). These bases pair specifically: adenine pairs with thymine, and cytosine pairs with guanine. This pairing is known as complementary base pairing, where adenine and thymine are bonded by two hydrogen bonds, while cytosine and guanine are connected by three hydrogen bonds. This structure allows DNA to maintain its double helix shape and is crucial for processes like DNA replication, transcription, and repair.
With in the gene pool, each allel is present in a certain poportion called allel frequency. Relative to the total nuber of alleles of that gene in the population. SOme alleles are very common in the population and threrefore have a high allel frequency. Biologist use the word Fitness to describe how good an organism is are leaving offspring in the next generation relative to how other organisms are at it. An organism with alleles bettter suited to tis enviroment is more likely to survive and produce more offspring and therefore will display a greater fitness.
Non-adaptive evolution refers to changes in the genetic makeup of a population that occur without direct influence from natural selection. This can include processes such as genetic drift, where random events cause certain traits to become more or less common in a population. Non-adaptive evolution does not necessarily lead to an increase in fitness or adaptation to the environment, as it is often driven by chance rather than the advantages of specific traits. Genetic drift can have a significant impact on small populations, leading to the fixation or loss of alleles through random sampling effects. In contrast to adaptive evolution, which is influenced by selection pressures favoring traits that enhance survival and reproduction, non-adaptive evolution highlights the role of randomness in shaping genetic diversity.
Multiple allele variants of gene create genetic diversity with the population - if there are only two or three allels in your small population, your population is displaying lower genetic diversity than a population that has five different alleles. Diploid organisms, which have two sets of chromosomes, can carry multiple alleles for a given gene, further contributing to the genetic diversity within the population. Changes in the allele frequency of a population due to pure chance are called genetic drift. Note that organisms there were lost did not have a disadvantage compared to the survivors not did the survivors have an advantage it was just dumb luck. A mutation refers to a permanent alteration in the DNA sequence that makes up a gene. Mutations can result from errors during DNA replication or as a consequence of environmental factors such as radiation or chemicals. Mutations is not the only way to introduce genetic variation into a population. Gene flow also called migration is any movement of individuals and the genetic material they carry fomr population to another. Gene flow can include pollen being blown to a new destination or people moving to a new city or country.
Natual selection now allmemebers of a species are the same-with in any population there is catiation in the physical characteristics of the indviduals. Darwin reasoned that if some these variants provided the individuals with a slight edge over their competitors in the grand struggle of life, they would be more likely to survive and pass these traits to their offspring. Over successive generations, these advantageous variations would become more common in the population while those variations that were less advantageous would become less common in the population. Darwin suggested that nature ( the enviroment) was in effect selecting for the forms of variants of and organism that were more successful in another. If the same population of variants was planced in two different enviroments, natual selection could eventually produce two different populations, each displaying particular variatioins or adaptions which provide for better scuess in wach particular enviroment.
Hominid vs Hominin
Hominid: Refers to all members of the biological family Hominidae, which includes great apes (such as orangutans, gorillas, and chimpanzees) as well as humans and their ancestors. Hominids are characterized by their larger size, complex social behaviors, and advanced cognitive abilities.
Hominin: Refers to the tribe Hominini, which includes modern humans, their immediate ancestors, and other species closely related to humans that have shared a more recent common ancestor. Hominins are distinguished from other hominids by traits such as bipedalism (walking on two legs), a more developed brain, and the use of tools.
In summary, all hominins are hominids, but not all hominids are hominins. Hominins focus specifically on the lineage leading to modern humans, while hominids encompass all great apes as well as humans.
Hominid Traits:
Size: Hominids, which include great apes and humans, are characterized by their larger body size compared to other primates.
Social Behavior: They exhibit complex social structures and behaviors, living in groups with intricate social dynamics.
Cognitive Abilities: Hominids possess advanced problem-solving skills and intelligence, with significant capabilities for communication and tool use.
Hominin Traits:
Bipedalism: Hominins are distinguished by their ability to walk on two legs, a key adaptation in their evolution.
Brain Development: They possess larger and more complex brains compared to other hominids, contributing to advanced problem-solving abilities and social interactions.
Tool Use: Hominins have the capacity to create and use tools, which plays a significant role in their survival and adaptation to different environments.
Social Structures: They exhibit complex social behavior, often living in communities with established social hierarchies and cooperative strategies.
Analtsis of the fossils invovles detailed measurements are careful comparisons of the fossils. The tools used are calipers and meter sticks to make measurments.
Cranial index=cranial breadth/cranial length x 100
Skull Proportion: Skull Proportion Index= Cranial breadth/Facial breadth x 100
Facial Proportion Index: Facial projection length is the distance between the front of the auditory canal and upper jaw. Total Skull length is the maxium distance between the back of the cranium and the from of upper jaw. Facial propotion index= Facial Projection length/Total skull length x 100
Vertebral Attachment Index: The hole in the base of the skull through which the spinal cord passes. Vertebral Attachment Index=Vertebral attachment length/total skull length x 100
Canine-Incisor Index: A long canine compared to the length of the incisors is a primitive condition among primates. Canine-Incisor Index = Length of canine teeth / Length of incisors x 100. This index helps in understanding the dietary habits and evolutionary adaptations of different primate species.
Tools used for Ecoli: A Spectrophotometer works by transmitting a beam of light through space toward a light sensor. The intensity of the light that passes through the sample is measured, allowing for the determination of the concentration of E. coli based on the optical density readings. Shaking incubator set to 35 degrees C.
The Carrying Capacity is the maxium number of individuals of a particular species that a particular enviroment can sustain indefinitely. When the number of individuals added to a population equals the number of individuals leaving a popualtion, there is no population growth and it growth rate is 0%. When this is due to teh enviroment, this level of population is said to have reached its carrying capacity, indicating that resources such as food, space, and water are being fully utilized.
The measure of growth of a population over a specific period of time is called it’s population growth rate. It is typically expressed as a fraction or percentafe of the total population. The population growth rate can be influenced by various factors, including birth rates, death rates, immigration, and emigration.
A group of individuals of the same species that share a common gene pool and share a common habitat is called populaiton. The term individual applies to both independent organisms or to individual cells with and organism, and poppulations can be small or large. The red blood cells in your veins can be considered a population, which in turn can be considered a population which in can be are part of a larger population of the cells that consitute your hematopoietic system which are in turn part of the of the complex population of cells that constiute your body. You are part of several nested populations as well ranging from your local community to the global human population.
Population Growth is the change in the number of individuals in a population. A positive growth reate indicates the population is increasing, while a negative growth indicates that the population is shrinking. Two of the most basic factors that affect the rate of population growth are the birth rate and the death rate. Simply put, a population will grow as long as more individuals are being born than are dying. COnsider an organism that doubles its population each generation. After one generation there are two individuals. Each of these are capable of producing two more progeny, so ager teh second generation out population is now composed of fourindividuals. The third generation produces another doubling and so does the forth, fifth. This type of growth is exponential and it produces a steep, rapidly ascending J-shaped growth curve. Nearly all populations will tend to grown exponentially as long as there are a surplus of resources available, which often occurs when the poplation is initally low and there is little to no competition.
The worls is deldom a perfect place, and resources are not unlimited. As the number of individuals with a population increases, they begin to compere for the limited resources, and this begins to negatively impact the rate at which the population grows. Maybe fewer resources result in fewer births or crowding increases suseptibility to disease. Under these types of pressures the rate at which the population grows continues to decrease until the number of births equals the number of deaths and which point the population ceases to expand. This type of mediating growth is called logistic frowth and it produces a sigmoidal or S-shaped curve. Nother that two types of curves are not excllusive the exponential growth of a population often evolves into a logistic growth pattern once the resources and enviromental conditioins become limiting.
When the number of individuals added to a population equals the number of individuals leaving a population, there is no population growth and its growth rate is 0%. When this is due to the enviroment, this level of population is said to have reached the enviroments carrying capacity. The carrying capcity is the maximum number of individuals of a particular speies that a particular enviroment can sustain indefinitely. Note that the same enviroment can and often does have different carrying capactities for different species. If the populations access to resources remains relatively inchanged then the carrying capacity and the population level remains stable. On occasion a rapidly growing population will temporarily surpass the carrying capacity, a condition call overpopulation, and a rapid a nd sometimes cataclysmic population readjustment occurs (sometimes called a population crash or collapse)
The loss of species population in every habitat that it occupies is called extinction. It is estimated that over 99% of all species that have ever existed have met this fate, including all the hominin species except us.
We will examine some of the properties of population dynamics using a common laboratory microorganism . Escherichia Coli is on of hundreds of the different baterial species that typically resides in your large intestines where it assista you in your digestion and the uptake of essential moecules like vitamin K. Most forms of E. coli do not pose a threat to you, but there are a few pathogenic (Diease causing) strains that, if they find their way into the food supply can cause mild to severe food poisoning. The E. coli you will be using is of a non pathongenic strain and poses no threat to your health during the experiment. We will focus on understanding its growth patterns, reproduction rates, and how environmental factors influence its population size.
The E.coli will be placed in a cuvette to measure its optical density, allowing us to monitor growth over time and assess how different conditions affect its proliferation. The cuvette is a cleat plastic vessel that has two types of sides: one side is flat for light transmission, while the other side is typically designed to hold the sample securely in place..
We will callibrate the spectrophotometer by insertind a cuvette containing 1.0ml steril growth media into the machine and pressing blank button. The sample serves as the control.
Light that does not reach the sensor is absorbed. Press the sample button to read the absorbance and record the value as well as the total timein the incubation.
The data will be generated using a scatter plot graph.
Your microbiota: The 100 trillion or so microorganisms that inhabit your body represent hundreds of different species, each adapted to a particular enviroment. There are bateria specially adapted to your skin, bacteria adapted to each and every orifice in the body.
Your Tumor Cells: tumores are abnormal masses of cells that form when cells acuire the ability to proliferate with constraing. However, solid tumor growth is typically limited to masses of only 1-2mm in size. Why? Becasue of carrying capacity. Reproduction requires resources and to the cells within your body this is oxygen and glucose. These are carried through the vascular system. Normal healthy tissues are innervated by blood vessels and are well supplied but becasue a tumor mass is atypical it is not well connected. Tumore cells therefore have limited resources enough only to support the development of a mass 1-2mm in size. Some tumore azquire mutations that grant the tumore the ability to stimulate the surrounding tissue to synthesize new blood vessels (called angiogenesis) for the sole purpose of linking the starving tumor with the body’s blood supply. Once connected the tumore have unlimitied resources and continue to grow unabated.
Food: the fishery business hasnot recovered since the 90’s. there are multiple factors that contributed to the Northwest Atlantic Fishery coloapse including overexploitation and govermental mismanagement, which led to the depletion of fish stocks and the disruption of marine ecosystems. In addition, climate change has also played a significant role in altering fish migration patterns, further complicating recovery efforts.
Your Species: Throughout earth’s history there has been 15-20 hominin species that have walked the earth. All but homo-sapiens have gone extinct. The easter head island a theriving culture collapsed due to overpopullation. Mayans collapsed due to inability to adjust to changing climate conditions.