Biol 103 Unit 3

. What is nondisjunction, and when does it occur? What is the most common result of aneuploidy? How can a karyotype reveal aneuploidy?

Non disjunction is the failure of chromosome or chromatids to separate during meiosis. Fertilization after non disjunction yields zygote with altered number of chromosomes. Aneuploidy is caused by errors in chromosome segregation Karyotype is the visual appearance of the chromosome in the cell nuclei. If you see more or less than 2 chromosomes on it, in each location, then it represent aneuploidy

Explain how genetic information flows in cell.

DNA is transcribed into RNA which is translated into proteins. This s called the central dogma

What enzyme replicates DNA starting at a replication "bubble"?

DNA polymerase

Understand the P, F1, F2 terminology.

P means parental generation and they are the only pure plants, F1 means first generation and they are all hybrids that show the dominant trait, F2 means second generation, which are the grandchildren of P or P: Parent generation F1: When parents are crossbred F1 generation is formed F2: When F1 generation is crossed F2 is formed another example The P generation is your grandparents, the F1 your parents, and the F2 is you (and any siblings).

What are some of the pros and cons to the accumulation of mutations in the cell's DNA?

Pro: Only beneficial if its through natural selection or evolution. They lead to new versions of proteins that help organisms adapt to changes in their environment. Beneficial mutations are essential for evolution to occur. They increase an organism's changes of surviving or reproducing, so they are likely to become more common over time. Con: Genetic disorder or Cancer

What is the enzyme that catalysis the transcription of RNA?

RNA Polymerase

What is the end result of a single mitotic cell division? • Trace the physical path of the chromosomes through the stages of mitosis (prophase, metaphase, anaphase, telophase/cytokinesis).

Results in two identical daughter cells. Identical to each other and identical to original parent cell. google

Define fitness (as the term is used in evolutionary theory)

Revolutionary fitness refers to the amount of offspring surviving to adulthood. The species with the highest number of offspring surviving to adulthood are the fittest

What is semiconservative replication?

Semiconservative replication produces two copies that each contained one of the original strands and one new strand. Conservative replication would leave the two original template DNA strands together in a double helix and would produce a copy composed of two new strands containing all of the new DNA base pairs.

Why is the Anopheles mosquito required for transmission of malaria?

The sexual reproduction of the parasites can only occur in Anopheles mosquitos

Define evolution

change in the genetic makeup in a population over time. Population means a group of individuals of the same species that live in the same area and interbreed with each other.

In a heterozygote, which allele determines the phenotype (dominant or recessive)?

dominant allele

Compare and contrast the two main stages of meiosis.

few cards above

Only one kind of cell is produced by meiosis in animals. Which cell type?

gametes

Know how many chromosomes, chromatids are present at each step of mitosis. • How does the size of chromosomes at the beginning of mitosis compare to the size of chromosomes at the end of mitosis? What accounts for the sizes of the chromosomes?

https://datbootcamp.com/biology-strategy/chromosome-and-chromatid-numbers-during-mitosis-and-meiosis/ ???

If given information about the parents, be able to predict the expected pattern of offspring phenotype & genotype

lecture

if you know information about an animal's genotype, be able to predict all the possible gametes produced by the animal.

lecture

What is the ultimate source of new alleles?

mutation

Which amino acid binds to stop codon

none

What is a monomer of the DNA polymer?

nucleotides

Where does DNA replication occur?

nucleus of a cell/ DNA replication happens anytime cell needs to divide in the S phase. It occurs because when we divide, we need enough DNA to pass to daughter cells

If given the nucleotide sequence of a single strand of DNA, be able to give the complementary sequence. See lecture slides for practice.

slides

What is a transfer RNA (tRNA)? Where are they located in the (eukaryotic) cell? Transfer RNAs bind to two things - what are they? What is the molecular machine that "supervises" that binding?

transfer RNA (tRNA) is a molecule that matches an amino acid for its corresponding mRNA. They are in the cytoplasm tRNA binds amino acid and mRNA Ribosome supervises the binding

Do X-linked recessive genetic diseases affect XX or XY individuals most often? Why?

x-linked recessive trait affects XY individuals most often since they have only 1 X allele, so if they inherit the recessive X allele with a genetic disease, they will express it. XY male XX female

What is the difference between a benign and a malignant tumor?

A malignant tumor has the ability to spread to other tissues and to initiate tumors at secondary sites, whereas a benign tumor does not spread. Benign tumors do not spread, and they are better candidates for removal by surgery. Malignant tumors, on the other hand, can spread throughout the body, invading other tissues and organs. They are far more destructive and difficult to treat.

What is a mutation and how could it end up changing a protein?

A mutation is a change in nucleotide sequence of DNA. This change leads to change in the RNA which eventually leads to change in protein

Cancer cells have escaped the regulation of the cell cycle checkpoints. What is the result?

DO NOT EXHIBIT DENSITY DEPENDENT INHIBITION NOR ANCHORAGE DEPENDENCE Cell cycle controls include miotic checkpoints, which make it so that the cell does not move to the next phase unless conditions are right.• Prevent sick or precancerous cells from dividing• Maintains proper cell numberHowever, if a cell accumulates enough mutations resulting either from genetic predisposition or exposure to cancerous, the cell will become cancerous and continously divide without those controls, creating tumors.

Evolution does not produce "perfect" organisms. Why are adaptations often compromises? (Hint: compare a racehorse with a wild mustang.)

Adaptions are often compromises For example: A racehorse is very fast, but it has thing legs that can be easily fractured. Whereas mustang , a wild type horse, has thicker bones than a racehorse. They do not fracture their bones as easily while compromising their speed.

What is the Hardy-Weinberg Principle? Name the five conditions that must be true in order for the alleles in a population to remain in equilibrium. What happens to the frequency of alleles in a population if any of those five conditions are not true?

Allele/genotype frequencies remain in equilibrium unless outside forces act to change those frequencies. 1) No selection 2) No mutation = Ultimate source of new allele is random mutations 3) No migration = No gene flow between distant populations 4) Large populations = Large populations are better at resisting changes in allelic frequencies 5) Random mating = Any two opposite mating type individuals must be equally likely to reproduce with each other According to Hardy Weinberg, if all 5 of these are true then evolution will not occur.

. Name common features of most cancers.

An out of control cell! Unregulated cell division Cells Tumor Tumor Health Problems & Death Cancer Cell common features: Abnormally high rates of cell division Can detach and invade other tissues (i.e. lose anchor dependence) = metastasis Cancer cells typically have many mutations in many genes

What is the difference between a haploid and a diploid cell?

Diploid cells are two full sets of chromosomes while haploid cells are one full set of chromosomes. In a diploid cell, person gets one set from their mom and one set from their dad. In a haploid cell, a person gets only one set that is a combination of chromosomes from their mom and dad.

When does cell division occur?

During the mitotic stage of the cell cycle WHY DOES CELL DIVISION HAPPEN? For growth/development, repair damaged cells, replace old cells or infected ones, and asexual reproduction (bacteria)

What do we mean when we say that two chromosomes are homologous?

Each of the chromosomes in the set from the male parent has a corresponding chromosome from the female parent.

Why does Watson & Crick's model of DNA immediately suggest a mechanism where it can be faithfully copied each time a cell divides? What aspect of this model must account for the variations between individuals (the sugar phosphate backbone, or the order of the nucleotide monomers)?

Each strand serves as a template on which a complimentary strand can be assembled

What is the most preventable cause of cancer in the U.S.?

Exposure to Cigarette Smoke/Smoking

Name the three cell cycle checkpoints described in class, explain where they occur during the cell cycle .• How might a growth factor affect the checkpoints? What happens to a cell if it can't proceed through the checkpoint (hint: that answer is different for the first checkpoint than for the second two). • What is signal transduction?

G1, G2, M Growth factor checks DNA before allowing it to pass G1 check point checks for: . Cell size . Nutrients . Growth factors . DNA damage If cant pass then it can either enter Go, try to repair, or get destroyed G2 check point checks for: . DNA damage . DNA replication completeness If cant pass then it can either try to repair, or get destroyed M checkpoint checks for chromosome division if not then killed process which conveys information from the outside of the cell to the inside of the cell. The G1 phase looks for growth factor if it is present then it attaches to the receptor protein, which sends signal to control system and lets cells go from G1 to S phase.

What happens if the variations in a population is insufficient for survival (as can be the case in a period of rapid environmental change)?

If variation is insufficient in the population, and if there is an environmental change, then if this change is detrimental for even a single individual, it will be detrimental for the entire population, as there is little to no variation,

Understand the steps of meiosis 1 and meiosis 2. • When are homologous chromosomes separated from each other? When are the sister chromatids separated?

Meiosis I 1. Prior to meiosis each chromosome is replicated. 2. Two new cells are produced which enter Meiosis II 3. Crossing over occurs. Interphase I Cells undergo a round of DNA replication, forming duplicate chromosomes Prophase I Each chromosome pairs with its corresponding homologous chromosomes to form a tetrad Metaphase I Spindle fibers attach to the chromosomes Anaphase I The fibers pull the homologous chromosomes toward opposite ends of the cell Telophase I and Cytokinesis Nuclear membrane forms. The cell seperates into two cells. Meiosis II 1. No replication. 2. Each entering cell has 2 chromatids. 3. Four haploid daughter cells produced. Prophase II Meiosis I results in two haploid (N) daughter cells, each with half the number of chromosomes as the original cell. Metaphase II The chromosomes line up in a similar way to the metaphase stage of mitosis. Anaphase II The sister chromatids separate and move toward opposite ends of the cell. Alleles segregate. Telophase II and Cytokinesis Meiosis II results in four haploid (N) daughter cells. In anaphase I, centromeres break down and homologous chromosomes separate. In anaphase II, the sister chromatids are separated.

What is the cellular process that generates gametes in animals?

Meiosis is a type of cell division that reduces the number of chromosomes in the parent cell by half and produces four gamete cells. This process is required to produce egg and sperm cells for sexual reproduction.

Meiosis generates haploid daughter cells from a diploid parent cell. Explain what that means in terms of the numbers of chromosomes present in the parent cell vs the daughter cells

Mitosis creates two identical daughter cells that each contain the same number of chromosomes as their parent cell. In contrast, meiosis gives rise to four unique daughter cells, each of which has half the number of chromosomes as the parent cell By the end of meiosis, the resulting reproductive cells, or gametes, each have 23 genetically unique chromosomes. The overall process of meiosis produces four daughter cells from one single parent cell. Each daughter cell is haploid, because it has half the number of chromosomes as the original parent cell

What kinds of cells undergo mitosis?

Mitosis is a type of cell division that results in two daughter cells each having the same number and kind of chromosomes as the parent nucleus, typical of ordinary tissue growth Mitosis occurs in what type of cell? Somatic/body

Define: incomplete dominance, pleiotropy, polygenic inheritance and give an example of each.

Neither allele is dominant, so phenotype is intermediate. (Ex: Skin color, height, voice pitch, hand size, hair texture) Pleiotropy. Pleiotropy occurs when one gene influences multiple phenotypic traits. Consequently, a mutation in a pleiotropic gene may have an effect on some or all traits simultaneously. polygenic triats. a trait that is controlled by several pairs of genes; different combinations of all the genes contribute to the trait in varying degrees. multiple allele traits. have more than 2 alleles of a particular gene for the same trait. Inheritance. the genetic characters transmitted from parent to offspring.

Do individuals evolve? Why or why not?

No. Individuals do not evolve, it is the population that evolves. Mutations can arise in individuals. If these mutations provide advantage, they may be passed down to future generations by the means natural selection. The leads to the evolutions of the population. Individuals can't evolve because for an evolution to occur frequency of a trait or allele needs to change over the period of time. Individuals can't do that

What are the three main causes of evolutionary change? Define each and give an example • We have spent the most time discussing natural selection in this course, because this is the primary mechanism by which organisms become adapted to their environment. Contrast the three ways that natural selection can alter variation in a population: stabilizing, directional, disruptive selection

3 Main causes 1) Natural selection: Random mutations that allow individuals of the population of a better chance of survival and live to reproduce. Example: green and red beetles. Green beetles camouflage with the color of the leaf while the red beetles standout. Hence birds are more likely to eat red beetles than green beetles 2) Genetic drift: Reduction in variation of different types of genotypes in a small population. This leads to disappearances of different types of genes. This can occur for example during many individuals dying in a natural disaster Example: Bottleneck 3) Gene flow: Gene flow is transfer of genetic material from one population to another;.

Trace the physical path of the chromosomes/chromatids through meiosis.

??

Explain how the following pieces of evidence contributed to the model of DNA as a double helix with complementary, antiparallel strands: 1) the amount of A always is equal to T & G is always equal to C, 2) the sugar-phosphates are on the outside of the helix,

Chargaff's rule ([A]=[T]; [G]=[C]) shows DNA strands are complimentary Sugar phosphate on outside of DNA. Both run in oppsoite directions, this shows DNA is antiparallel

What is a codon, and what is it made of? How many nucleotides are needed to code for one amino acid? What do we mean by 'genetic code'? Why do we say that the genetic code is universal?

Codon is a 3-letter code that codes for amino acids. These codons are made up of nucleic acids. 3 nucleotides are needed to code for amino acid Genetic code. Genetic code is the set of instructions, in the form of nucleotide triplets, that translate a linear sequence of nucleotides in mRNA into a linear sequence of amino acids in a protein. it ensures that a human gene can be composed of the correct and functional amino acids, even when made in another organisms. if the genetic code were not universal, we would not be able to create transgenic organisms.

.DNA is packaged together with proteins inside the nucleus. Why does DNA need special mechanisms to physically fit inside the (eukaryotic) cell nucleus? The "baseline" level of DNA packaging that always is present in cells is chromatin. During cell division, that chromatin is further compacted down to form the chromatids.

Condensing the DNA into tightly packed chromosomes makes the process of chromosome alignment and separation during mitosis more efficient. To package DNA inside the nucleus, cells wrap their DNA strands around scaffolding proteins to form a coiled condensed structure called chromatin. ... A nucleosome contains eight histones wrapped by DNA, and serves as the repeated primary unit for organizing the higher levels of chromatin structure.

Why are many populations of mosquitos resistant to insecticides like DDT? Explain in terms of natural selection.

Countries all over the world used DDT in an attempt to kill off Anopheles mosquitos. The mosquitos this event are more resistant to DDT

Where are the covalent bonds in a DNA molecule? the hydrogen bonds? Why do we say the strands of DNA are antiparallel?

Covalent bonds in the DNA are between the sugar phosphate backbone, whereas the hydrogen bonds are between the nucleic acids A and T have 2 hyrdogen bonds. G and C have 3 hydrogen bonds The sugar and phosphate make up the backbone, while the nitrogen bases are found in the center and hold the two strands together. ... Due to the base pairing, the DNA strands are complementary to each other, run in opposite directions, and are called antiparallel strands.

What is the difference between proto-oncogenes and tumor suppressor genes? • How does a proto-oncogene become an oncogene? What is the result? • What is apoptosis, and what does it have to do with cancer prevention? • How many mutations (minimum) must accumulate in a cell before out of control-of-control cell division results?

Gatekeeper genes :Proto-oncogenes and Tumor suppressor genes Tumor Suppressor Genes: Genes that turn OFF or DECREASE the rate of celldivision. Genes that repair DNA mistakes. Genes that play a role in apoptosis. Proto-oncogenes Genes that turn ON or INCREASE the rate of cell division. When these genes are active CELLS GROW and DIVIDE. When normal cells stopdividing, the genes turn off. A proto-oncogene is a normal cellular gene that typically plays a role in cell division. It can be altered by mutation to become an oncogene and thereby cause cancer. A type of cell death in which a series of molecular steps in a cell lead to its death. This is one method the body uses to get rid of unneeded or abnormal cells. The process of apoptosis may be blocked in cancer cells. Also called programmed cell death. Apoptosis in Cancer The loss of apoptotic control allows cancer cells to survive longer and gives more time for the accumulation of mutations which can increase invasiveness during tumor progression, on average, 1 to 10 mutations are needed for cancer to emerge. (Unsure)

What is meant by the term "gene loci" in the context of homologous chromosomes?

Gene locus is a place on chromosome where gene is found. if you have homologous chromosomes contain the same gene loci

Define the terms gene, allele, genotype, phenotype, homozygous, heterozygous, dominant, recessive.

Genes are segments of DNA found on a chromosome that determine the inheritance of a particular trait. They are responsible for the inherited characteristics that distinguish one individual from another. Chromosomes. Chromosomes are structures found in the nucleus of a cell that contains the genetic information (DNA). An allele is an alternative form of a gene (one member of a pair) that is located at a specific position on a specific chromosome. These DNA codings determine distinct traits that can be passed on from parents to offspring Genotype refers to the alleles you possess for a particular gene or set of genes. Phenotype is the physical trait itself, which may be influenced by genotype and environmental factors. What factors cause quantitative variation in a trait within a population. same^ Homozygous means that. An offspring either has 2 copies of the dominant allele or 2 copies of the recessive allele. Heterozygous means that. The offspring has 1 copy of the dominant allele and 1 copy of the recessive allele. heterozygous. an organism that has two different alleles for a trait (hybrid) Punnett Square. a chart that shows all of the possible combinations of alleles that can result in a genetic cross. Dominant traits are always expressed when the connected allele is dominant, even if only one copy of the dominant trait exists. Recessive traits are expressed only if both the connected alleles are recessive.

What kinds of body processes require cellular division? Give definitions and examples of asexual and sexual reproduction. • Under what conditions do cells replicate themselves? Contrast cells in muscle vs cells in your skin

Growth and development Maintenance of the body Reproduction Wound Healing ASEXUAL PRODUCTION: genetically identical offspring / one parent produces offspring that are genetically identical to the parent. EXAMPLE: Bacterium undergoes binary fission in which the cell divides into two along with the nucleus. Blackworms or mudworms reproduce through fragmentation. Hydras reproduce through budding. Organisms such as copperheads undergo parthenogenesis. SEXUAL REPRODUCTION: The process of forming a new individual from two parents./ produces unique offspring Meiosis - Cell division in which 4 cells are produced at the same time with half the number of chromosomes as parents cells. Artificial Methods Asexual | Sexual-cloning | -artificial insementation in vitro-tissue culture | [genetic engineering] Vegetive Propagation - a form of asexual reproduction using the vegetation part of a plant . (not seeds, flowers, or fruit)Ex. cuttings, rooting, bulbs, tuber, potatoes, runners, grafting. Fertilization - The joining of an egg and sperm to form a zygote (fertilized egg)

Why do many treatments for cancer often have very serious side-effects?

In order to treat cancer, the rapidly dividing cells must be removed surgically, killed, or at least slowed down. they can affect normal, healthy cells that are fast-growing, too. Damage to healthy cells causes side effects

Define the terms "independent assortment" and "crossing over" (homologous recombination). These processes generate unique gametes. Where/when do they occur? Do these processes generate new alleles or different combinations of alleles?

Independent assortment means genes independently separate from one another when reproductive cells develop. Crossing over means exchange of homologous chromosome resulting in a mixture of parental characteristics in off spring. during meiosis in the sex organs- occurs in METAPHASE I when homologous chromosomes line up at the four chromatid stage Crossing over occurs during prophase I of meiosis I. It involves the switching of genes between homologues non-sister chromatids which allows the mixture of maternal and paternal genetic material with new, recombinant chromosomes. crossing-over process results in an unlinking and recombination of parental genes. ... However, it does not result in new alleles. independent assortment during anaphase creates sets of chromosomes with new combinations of alleles.

How does the sickle cell hemoglobin trait confer resistance to infection by the malaria parasite? who is homozygous vs heterozygous for the sick cell trait in terms of malaria infection and sickle cell disease. Compare the outcomes for an individual

Several studies suggested that, in one way or another, sickle hemoglobin might get in the way of the Plasmodium parasite infecting red blood cells, reducing the number of parasites that actually infect the host and thus conferring some protection against the disease. if youre homozygou u get sickle cell trait but proected against malaria if hetro then neither

What is the role of the spindle fibers (the assembly of motor proteins and microtubules that facilitate chromosome movement)?

Spindle fibers form a protein structure that divides the genetic material in a cell. The spindle is necessary to equally divide the chromosomes in a parental cell into two daughter cells during both types of nuclear division: mitosis and meiosis. During mitosis, the spindle fibers are called the mitotic spindle.

What are the two phases of the cell cycle? When is DNA duplicated? What is the name of the enzyme that replicates DNA? Does that enzyme do a perfect job? What is the result of its mistakes? • About how often does the DNA replication enzyme make mistakes? What occurs in: G1, S, G2? What is Go ("G-naught")? What situation results in a cell entering Go? What are the two things that must be accomplished in M phase?

Two phases: Interphase (G1, G2, S) Mitotic Phase (M) Replicated in the S phase DNA polymerase replicates DNA. No it does not do a perfect job. Mistakes can occur and can result in cancer Mistakes occur 1/10,000bp What event occurs during the G1 phase? the newly formed cell grows to maturity. Some cells will stay in a resting state after mature called the G0 (G zero) phase until the cell needs to divide. What event occurs during the S phase? DNA is synthesized through a process called DNA replication. What is G2 phase? A stage of interphase. Second growth. What is Go phase? Occurs in G1, here cell is not dividing or preparing to divide. During the mitotic (M) phase, the cell divides its copied DNA and cytoplasm to make two new cells. M phase involves two distinct division-related processes: mitosis and cytokinesis. In mitosis, the nuclear DNA of the cell condenses into visible chromosomes and is pulled apart by the mitotic spindle, a specialized structure made out of microtubules. Mitosis takes place in four stages: prophase (sometimes divided into early prophase and prometaphase), metaphase, anaphase, and telophase. You can learn more about these stages in the video on mitosis. In cytokinesis, the cytoplasm of the cell is split in two, making two new cells. Cytokinesis usually begins just as mitosis is ending, with a little overlap. Importantly, cytokinesis takes place differently in animal and plant cells.

Recall our discussion of moving the gene for jellyfish GFP into a nematode (worm). Will the worm glow green? Why does this suggest a universal mechanism for the production of proteins in all organisms?

Yes it will glow, since the gene from DNA needs to be expressed as a protein to get the green glow, we can say that the mechanism of production of protein is universal.

chromosome, chromatin, chromatid, sister chromatids, diploid, haploid, homologous chromosomes, somatic cells, gametes

a threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes. the material of which the chromosomes of organisms other than bacteria (i.e., eukaryotes) are composed. It consists of protein, RNA, and DNA. each of the two threadlike strands into which a chromosome divides longitudinally during cell division. Each contains a double helix of DNA. either of the two identical chromatids that are formed by replication of a chromosome during the S phase of the cell cycle, are joined by a centromere, and segregate into separate daughter cells during anaphase Diploid is a cell or organism that has paired chromosomes, one from each parent. ... A normal eukaryote organism is composed of diploid cells, one set of chromosomes from each parent. However, after meiosis, the number of chromosomes in gametes is halved. Haploid is the term used when a cell has only one set of chromosomes. A normal eukaryote organism is composed of diploid cells, one set of chromosomes from each parent. However, after meiosis, the number of chromosomes in gametes is halved. Homologous chromosomes are chromosome pairs, one from each parent, that are similar in length, gene position and centromere location. ... Each carries the same genes in the same order, but the alleles for each trait may not be the same. A somatic cell is any cell of the body except sperm and egg cells. Somatic cells are diploid, meaning that they contain two sets of chromosomes, one inherited from each parent. Gamete. A sex cell that contains the haploid of chromosomes. Haploid. The number of chromosomes in a gamete of an organism.

All cancers are characterized by __________

abnormally high rates of cell division