Biology Final

State the chromosomal theory of inheritance

genes are on locus of chromosomes and chromosomes get segregated resulting in independent assortment

What is the function of a histone?

more than a fifth of the histones amino acids are positively charged (lysine or arginine) and therefore bind tightly to the negatively charged DNA .

Describe the function of RNA polymerase

catalyzes syntheizing of RNA by linking together RNA nucleotides complementary to a DNA template strand.

describe the inheritance of the sickle cell allele

caused by amino acid in the hemoglobin protein of red blood cells. 2 = full blown, 1= possibly affecting phenotype

4: Meiosis II is similar to mitosis in that

A; sister chromatids separate during anaphase

What is a genes locus?

DNA's place on chromosome

#5 which component is not directly involved in translation

b; DNA...

What types of bonds connect sugars to phosphates in the backbones of DNA?

covalent bonds

Prepare to answer questions about the following; synapsis, crossing over, chiasmata (pg 260)

"Each homologous pair undergoes synapsis and crossing over between nonsister chromatids with the subsquent appearance of chiasmata"

What will be the results of chemically modifying one nucleotide base of a gene

...When a nucleotide base is altered chemically, its base-pairing characteristics may be changed. When that happens, an incorrect nucleotide is likely to be incorporated into the complementary strand during the next replication of the DNA, and successive rounds of replication will perpetuate the mutation. Once the gene is transcribed, the mutated codon may code for a different amino acid that inhibits or changes the function of a protein.

Explain how three processes unique to meiosis generate a great deal of genetic variation

1) During independent assortment in metaphase I a daughter cell of meiosis I randomly inherits either a maternal or paternal chromosome 2) Due to crossing over, they share genetic information 3) Random fertilization; any sperm of a large number containing many possible genetic combination can fertilize any egg or a similarly large number of possible combinations.

A man has six gingers on each hand and six toes on each foot. His wife and their daughter have the normal number of digits. Remember that extra digits is a dominant trait. What fraction of this couples children would be expected to have extra digits

1/2

14.2 #1 For any gene with a dominant allele A and recessive allele a, what proportions of the offspring from an AA x Aa cross are expected to be homozygous dominant, homozygous recessive, and heterozygous?

1/2 homozygous dominant (AA), O homozygous recessive (aa), and 1/2 heterozygous (Aa)

15.2 cc# 2 Neither Tim nor Rhoda has Duchenne muscular distrophy, but their firstborn son does have it. What is the probability that a second child of this couple will have the disease? What is the probability that a second child of this couple will have the disease? What is the probability if the second child is a boy? A girl?

1/4 (1/2 chance that the child will inherit the X carrying the disease allele from his mother) if the child is a boy, there is 1/2 chance he will have the disease; a female would have zero chance (but 1/2 chance of being a carrier)

#7 Red-green color blindness is caused by a sex-linked recessive allele. A color-blind man marries a woman with normal vision whose father was color-blind. What is the probability that they will have a color-blind daughter? What is the probability that their first son will be color-blind?

1/4 for each daughter (1/2 chance that child will be female x 1/2 chance of a homozygous recessive genotype); 1/2 for first son

in figure 13.4, how many DNA molecules (doble helices) are present

12; each set of 6 chromosomes is duplicated so 12

When did Mendel do his work?

1857

What is the ploidy status of a zygote

2n or 46 chromosomes for a human, think 2 sets of chromosomes = 2n

What is a trisomy

3 chromosomes in zygote (the cell has 2n + 1 chromosomes)

Explain the phenotypic ratio that is expected in a monohybrid cross.

3:1, a genetic cross between two different alleles would cause 3 dominant and one recessive traits in the phenotype (monohybrid: heterozygous for the one particular character being followed in the cross)

How may cells result from meiosis?

4 daughter cells

What is the ploidy status of a somatic cell?

46 chromosomes

What ratio is expected in a dihybrid cross?

9:3:3:1, think 4 across top crossed with 4 across bottom AbAb x AbAb

A pea plant heterozygous for inflated pods (li) is crossed with a plant homozygous for constricted pods (ii). Draw a punnett square for this cross. Assume that pollen comes from the ii plant

A cross of li x ii wold yield offspring with a genotypic ratio of 1 li: 1 li (2:2 is an equivalent answer) and a phenotypic ratio of 1 inflated : 1 constricted (2:2 is equivalent)

Describe the process of gene expression, by which a gene affects the phenotype of an organism

A gene contains genetic information in the form of nucleotide sequence. The gene is the first transcribed into an RNA molecule, and a messenger RNA molecule is ultimately translated into a polypeptide. The polypeptide makes up part or all of a protein, which performs a function in the cell and contributes to the phenotype of the organism

16.3 #1 Describe the structure of a nucleosome, the basic unit of DNA paching eukaryotic cells

A nucleosome is made up of eight histone proteins, two each of four different types, around which DNA is wound. Linker DNA runs from one nucleosome to the next.

What is a monosomy

A zygote that is an aneuploid (abnormal in chromosomes), no copy of chromosome. I chromosome (so the cells has 2n -1 chromosomes)

1: A human cell containing 22 autosomes and a Y chromosome is

A; a sperm

A black guinea pig crossed with an albino guinea pig produces 12 black offspring. When the albino is crossed with a second black one, 7 blacks and 5 albinos are obtained. What is the best explanation for this genetic outcome? Write genotypes for the parents, gametes, and offspring

Albino (b) is a recessive trait; black (B) is dominant. First cross: parents BB x bb; gametes B and b; offspring all Bb (black coat), The black guinea pig in the second cross is a heterozygote. Second cross; parents Bb x bb; gametes 1/2 B and 1/2 b (heterozygous parent) and b; offspring 1/2 Bb and 1/2 bb

#7 A biochemist isolates, purifies, and combines in a test tube a variety of molecules needed for DNA replication. When she adds some DNA to the mixture, replication occurs, but each DNA molecule consists of a normal strand paired with numerous segments of DNA a few hundred nucleotides long. What has she probably left out of the mixture?

B, DNA ligase

#3 In analyzing the number of different bases in a DNA sample, which result would be consistent with the base-pairing rules?

B; A + G = C+T

3: Homologous chromosomes move toward opposite poles of a dividing cell during

B; meiosis I

Explain why human offspring resemble their parents but are not identical to them

Because of their genetic variation. They have two parents and so they have a combination of genes with specific traits inherited

17.2 #1 Compare DNA polymerase and RNA polymerase in terms of how they function, the requirement for a template and primer, the direction of synthesis, and the type of nucleotides used.

Both assemble nucleic acid chains from monomer nucleotides whose order is determined by complementary base pairing to a template strand. Both synthesize in promer, but RNA polymerase can start a nucleotide chain from scratch. DNA polymerase uses nucleotides with the sugar deoxyribose and the base T, whereas RNA polymerase uses nucleotides with the sugar ribose and the base U

What function do the 5' cap and the poly-A tail serve on a eukaryotic mRNA

Both the 5' cap and the poly-A tail help the mRNA exist from the nucleus and then, in the cytoplasm, help ensure mRNA stability and allow it to bind to ribosomes

#5 In a nucleosome, the DNA is wrapped around

C, Histones

6:If we continued to follow the cell lineage from question 5, then the DNA content of a single cell at metaphase of meiosis II would be

C; x

16.1 #1 A fly has the following % of. nucleotides in its DNA: 27.3% A, 27.6% T, 22.5% G, and 22.5% C How do these numbers demonstrate Chargaffs rule about base ratios

Chargaff's rule about base ratios states that in DNA, the % pf A amnd T are essentially the same, as those of G and C. The fly data are consistent with that rule (slight variations are most likely die to limitations of analytical technique)

16.2 #1 What role does complementary base pairing play in the replication of DNA

Complementary base pairing ensures that the two daughter molecules of the parental molecule separate, each serves as a template on which nucleotides are arranged, by the base-pairing rules, into new complementary strands

5: If the DNA content of diploid cell in the G1 phase of the cell cycle is x, then the DNA content of the same cell at metaphase of meiosis I would be

D; 2x

How do asexually reproducing organisms produce offspring that are genetically identical to each other and to their parents

DNA is copied and passed to two daughter cells through mitotic cell division. The offsprings genomes are the exact same as the parent's genomes.

What molecules are found in chromatin?

DNA, histones, protein

17.3 #1 How can human cells make 75,000 -100,000 different proteins, given that there are about 20,000 human genes?

Due to alternative splicing of exons, each gene can result in multiple different mRNAs and can thus direct synthesis of multiple different proteins.

16.3 #2 Interphase chromosomes appear to be attached to the nuclear lamina and perhaps also the nuclear matrix. Describe these two structures.

Euchromatin is Chromatin that becomes less compacted during interphase and is accessible to the cellular machinery responsible for gene activity. Heterochromatin, on the other hand remains quite condensed during interphase and contains genes that are largely inaccessible to this machinery

What is a pedigree

Family tree describing traits of parents and children in generations

17.4 #1 What two processes ensure that the correct amino acid is added to a growing polypeptide chain

First, each aminoacyl-tRNA synthetase specifically recognizes a single amino acid and attaches it only to an appropriate tRNA. Second, a tRNA charged with it specific amino acid binds only to an mRNA codon for that amino acid

Match the term on the left with a statement on the right

Gene, I. Allele, e. Character, g. Trait, b. Dominant allele, j. Recessive allele, a. Genotype, k. Phenotype, h. Homozygous, c. Heterozygous, f. Testcross, i. monohybrid cross, d.

14.4 # 2 Explain how the change of a single amino acid in hemoglobin leads to the aggregation of hemoglobin into long rods

Glu (sixth amino acid) replaced by Valine (Val). The primary structure of a protein (its amino acid sequence) determines the shape of the protein's and determines the function of the red blood cells

What did Mendel demonstrate using a mono hybrid cross?

His first law of heredity- segregation

What did Mendel demonstrate using a dihybrid cross?

His second law of heredity - independent assortment

What is the difference in chromosomes between a human male and human female.

Human females have a pair of XX chromosomes, male have one X and Y.

What role is played by DNA repair systems in the cell

If the chemical change in the base is detected and repaired by the DNA repair system before the next replication, no mutation will result

Why are specific alleles of two genes that are farther apart more likely to show recombinant than those of closer genes?

If they are farther apart they are more likely to cross over, when they are closer together they have less room for cross over

17.3 #2 How is RNA splicing similar to editing a video? What would introns correspond to in this analogy?

In editing a video, segments are cut out and discarded (like introns) and the remaining segments are joined together (like exons) so that the regions of joining ("splicing") are not noticeable

When Mendel crossed true-breeding purple - and white flowered pea plants, the white flowered trait disappeared from the F1 generation and reappeared in the F2 generation. Use the genetic terms to explain why that happened

In the F1 generation the white flowered trait disappeared because the purple flowered traits was dominant, however in the F2 generation the white flowered trait reappeared because if the 3:1 ratio

16.2 #3 What is the relationship between DNA replication in E Coli

In the cell cycle, DNA synthesis occurs during the S phase, between the G1 and G2 phase of interphase. DNA replication is therefore complete before the mitotic phase begins

17.5 #1 What happens when one nucleotide pair is lost from the middle of the coding sequence of a gene

In the mRNA, the reading frame downstream from the deletion is shifted, leading to a long string of incorrect amino acids in the polypeptide , and in most cases, a stop codon will arise, leading to premature termination. The polypeptide will most likely be nonfunctional

What is the difference between an intron and an exon

Intron: the nonocoding segments of nucelic acid that lie between coding regions (intervention sequences) Exon: The other regions are eventually expressed, usually by being translated into amino acid sequences The introns are cut out from the molecule and the exons are joined together, forming an mRNA molecule

Explain the cause of down syndrome

It's an aneuploid condition (abnormal chromosomes). The result of an extra chromosome 21, so that each body cell has a total of 47 chromosomes

14.4 # 3 Joan was born with six toes on each foot, a dominant trait called polydactyly. Two of her five siblings and her mother, but not her father, also have extra digits. What is Joan's genotype for the number of digits character? Use D and d to symbolize the alleles for this character

Joan's genotype is Dd. Because the allele for polydactyly pressed in people with either the DD or Dd genotype. But because Joan's father does not have polydactyly, his genotype must be dd, which means that Joan inherited a d allele from him. Therfore, Joan, who does have the trait, must be heterozygous

During which round of meiosis are the chromosomes reduced from diploid to haploid?

Meiosis I

In what important ways are methaphase I and anaphase I of meiosis different from metaphase and anaphase of mitosis?

Metaphase of meiosis I: Chromosomes line up as homologous pairs (2 pairs of identical chromatids or 4 sister chromatids) on the metaphase plate; in Mitosis individual chromosomes line up (2 sister chromatids) Anaphase I of meiosis I: Homologs separate from each other; sister chromatids remain joined at the centromere. In Mitosis the 2 sister chromatids separate

17.3 #3 What would be the effect of treating cells with an agent that removed the cap from mRNAs

Once the mRNA has existed the nucleus, the cap prevents it from being degraded by hydrolytic enzymes and facilitates its attachment to ribosomes. If the cap were removed from all mRNAs, the cell would no longer be able to synthesize any proteins and would probably die

Describe the functions of the E, P, and A sites on the ribosome

P site: holds the tRNA carrying the growing polypeptide chain A site: holds the tRNA carrying the next amino acid to be added to the chain E site: is the exit side for discharged tRNAs from the ribosome ...

Name and describe the three possible genotypes that can result from a monohybrid cross

PP, Pp, Pp, pp. Think Pp crossed with Pp

Give an example of an x linked gene

color blindness

The pedigree below traces the inheritance of alkaptonuria, a biochemical disorder. Affected individualism indicated here by the colored circles and squares, are unable to metabolize a substance called alkapton, which colors the urine and stains body tissues. Does alkaptonuria appear to be caused by a dominant allele or by a recessive allele? Fill in the genotypes of the individuals whose genotypes can be deduced. What genotypes are possible for each of the other individuals?

Recessive. All affected individuals (Arlene, Tom, Wilma, and Carla) are homozygous recessive aa. George is Aa, since some of his children with Arlene are children with one affected parent. Michael also is Aa, since he has an affected each have either the AA or Aa genotype

#2 pseudohypertrophic muscular dystrophy is an inherited disorder that causes gradual deterioration of the muscles. It is seen almost exclusively in boys born to apparently normal parents and usually results in death in the early teens. Is this disorder caused by dominant or a recessive allele? Is its inheritance sex-linked or autosomal? How do you know? Explain why this disorder is almost never seen in girls

Recessive; if the disorder were dominant, it owuld affect at least one parent of a child born with the disorder. The disorder's inheritance is sex linked because its seen only in boys. For a girl to have the disorder, she would have to inherit recessive alleles from both parents. This would be very rare, since males with the recessive allele on their x chromosome die on their early teens

14.1 #3 In some pea plant crosses, the plants are self-pollinated. Refer back to concept 13.1 and explain whether self-pollination is considered asexual or sexual reproduction

Self pollination is sexual reproduction because meiosis is involved in forming gametes, which unite during fertilization. As a result, the offspring in self-pollination are genetically different from the parent.

What is meant to by the term "true-breeding"

Self-pollinating plants that produce only the same variety as the parent plant; ex: a plant with purple flowers is true-breeding of the seeds produced bu self-pollination in successive generations all give rise to plants that also have purple flowers

What is the difference between autosomal chromosomes and sex chromosomes?

Sex chromosomes (x and y) determine sex, autosomal determine body characters

A horticultarist breeds orchids, trying to obtain a plant with a unique combination of desirable traits. After many years, she finally succeeds. To produce more plants like this one should she crossbreed it with another plant or clone it? Why?

She should clone it, if she crossbreeds it the plant would have a combination of traits that were passed from both parents.

How are the chromosomes in a cell at metaphase of mitosis similar to and different from the chromosomes in a cell at metaphase of meiosis II?

Similar: sister chromatids in both, chromosomes at metaphase plate Differ: in mitosis chromatids are genetically identical, in meiosis genetically distinct because of crossing over

What characteristic of the sex chromosomes allowed Morgan to correlate their behavior with that of the alleles of the eye color gene

That a specific gene is carried on a specific chromosome (eye color gene on the x chromosome).

What is a promoter

The DNA sequence where RNA polymerase attaches and initiates transcription

From which parents do human children inherit their X chromosome? Their Y chromosome

X chromosomes can come from mom or dad, y chromosome comes from dad

Both members of a couple know that they are carriers of the cystic fibrosis allele. None of their three children has cystic fibrosis, but any one of them might be a carrier. They would like to have a forth child but are worried that it would very likely have the disease, since the first three do not. What would you tell the couple? Would it remove some more uncertainty in their prediction if the could find out from genetic test whether the three children are carriers?

The chance of the fourth child having cystic fibrosis is 1/4, as it was for each of the other children, because each birth is an independent event.

Each sperm of a pea plant contains seven chromosomes. What are the haploid and diploid numbers for this species

The haploid number is (n) 7; the diploid number (2n) is 14

# 10 Women born with an extra X chromosome (XXX) are generally healthy and indistinguishable in appearance from normal XX women. What is a likely explanation for this finding? How could you test this explanation?

The inactivation of two x chromosomes in XXX women wold leave them with one genetically active X, as in women with the normal number of chromosomes. Microscopy should reveal two Barr bodies in XXX women.

15.1 cc#2 Review the description of meiosis in figure 13.8 and Mendel's two laws in concept 14.1. What is the physical basis for each of Mendel's laws?

The physical basis for the law of segregation is the separation of homologs in anaphase I. The physical basis for the law of independent assortment is the alternative arrangements of homologous chromosome pairs in metaphase I.

14.1 #2 List all gametes that could be made by a pea plant heterozygous for seed color, seed shape, and pod shape (YyRrli). How large a Punnette square would you need to draw to predict the offspring of a self-pollination of this "trihybrid"

The plant could make eight different gametes (YRI, YRI, Yrl, Yri, yRl, YRi, yrl, and yri) To fit all the possible gametes in a self-pollination, a Punnette square would need 8 rows and 8 columns. It would have spaces for the 64 possible unions of gametes in the offspring.

How does the presence of a nuclear envelope affect gene expression in eukaryotes

The presence of a nuclear envelope in eukaryotes means that transcription and translation are separated in space and therefore in time. This separation allows other processes to occur and provides other steps at which gene expression can be regulated

17.2 #2 What is a promoter, and is it located at the upstream or downstream end of a transcription unit?

The promoter is the region of DNA to which RNA polymerase binds to begin transcription, and it is at the upstream end of the gene (transcription unit)

Polygenic inheritance results in continuous variation for the trait that is under consideration. How does this differ from the traits Mendel studied?

The traits that Mendel studied were limited to either or

What is the relationship between two chromosomes that are homologs?

They are chromosomes that 1) carry the same inherited characters 2) They are the same length 3) centromere position 4) staining pattern.

Extensions of Mendelian inheritance for a single gene: Compare complete dominance to incomplete dominance

Think phenotype result because of genotype dominance. Complete dominance of one allele: Heterozygous phenotype same as that of homozygous dominant; the F1 offspring always looked like one of the two parental varieties because one allele in a pair showed complete dominance over the other Incomplete dominance of either allele: Heterozygous phenotype intermediate between the two homozygous phenotypes ; neither allele is completely dominant and the F1 hybrids have a pheotype somewhere between the two parental varieties.

9: How can you tell the cell in question 8 is undergoing meiosis, not mitosis

This cell must be undergoing meiosis because homologous chromosomes are associated with each other at the metaphase plate; this does not occur in mitosis

Describe the processes of protein synthesis, including transcription and translation. On DNA, and with regard to protein synthesis, what is the difference between the template strand and the coding strand

Transcription is the synthesis of RNA using information in the DNA. The two nucleic acids are are written in different forms and the information is rewritten from DNA to RNA. RNA carries the message to the protein synthesizing machinery of the cell. Translation is the syntheis of polypeptide using the information in the mRNA. The cell translates the nucleotide sequence of an mRNA molecule into the amino acid sequence of a polypeptide The difference between the template strand and the coding strand is that the template strand is the only strand of DNA being transcribed. The coding strand is the strand with the copy of the template that is coded to make proteins

explain how chromosomes determine sex in humans and almost all other mammals

Two X chromosomes result in female, one X and one Y result in male

How do we acquire our chromosomes?

We inherit them from our parents through fertilization

What is the difference with regard to expected genotypic and phenotypic ratios

complete dominance ratios: Incompete dominance ratios: 1:2:1

16.1 #2 Given a polynucleotide sequence such as GAATTC, can you tell which is the 5' end? If not, what further information do you need to identify the ends

You can't tell which end is the 5' end. You need to know hwich end has a phosphate group on the 5' carbon (the 5' end) or which end has an -OH group on the 3' carbon (the 3' end)

What is a DNA replication fork?

a Y shaped region where the parental strands of DNA are being unwound

What is a mutation

a change in the nucleotide sequence of an organism's DNA or in the DNA or RNA of a virus ...

What is a recombinant chromosome and how are they formed during meiosis?

a chromosome with a combination of genes from two parents formed in prophase I when homolog chromosomes cross over

what does it mean when a gene is called a "sex-linked" gene?

a gene located on either sex chromosome

What is the function of a TATA box

a promotor DNA sequence helps the enzyme polymerase get downstream to the initiation site

What is a histone?

a protein responsible for the first level of DNA packing in chromatin

Is a set of chromosomes haploid or diploid

a set is haploid, 2 sets of two sister chromatids is diploid

What is a codon

a set of three nucleotides

What is meant by the term "polygenic inheritance"?

a single trait is controlled by 2 or more sets of alleles; ex: skin and eye color

Describe the modifications made to a pre-mRNA during RNA processing in a eukaryotic cell

both ends of the primary transcript are altered. Certain, interior sections of the RNA molecule are cut out and remaining parts spliced together.

How does DNA control metabolism?

by directing cells to make specific enzymes and other proteins, via the process of gene expression

#3 The anticodon of a particular tRNA molecule is

a; complementary to the corresponding mRNA codon ...

#4 Which of the following is not true of RNA processing

a; exons are cut out before mRNA leaves the nucleus ...

What is meant by the term "aneuploidy"

abnormal number of chromosomes caused by abnormal gamete uniting with normal gamete to form zygote

Compare and contrast asexual reproduction and sexual reproduction

asexual reproduction: one parent sexual reproduction: is done so through fusion of gametes of two organisms, two parents

#1 in eukaryotic cells, transcription cannot begin until

b; several transcription factors have bound to the promoter

Explain why a pair of linked genes will yield variable ratios of "parental" vs "recombinant" genotypes - which do not come out in Mendelian ratios

because crossing over can occur with linked genes

Why are nasty recessive alleles rather than nasty dominant alleles more likely to persist in a population?

because recessive alleles can be passed from one generation to the next by heterozygous carriers, a lethal dominant alleles are less likely to be passed on to offspring because it often causes death before individuals mature

15.3 cc# 1 When two genes are located on the same chromosome, what is the physical basis for the production of recombinant offspring in a testcross between a dihybrid parent and a double mutant (recessive) parent

crossing over during meiosis I in heterozygous parent produces some gametes with recombinant genotypes for the two genes. Offspring with a recombinant phenotype arise from fertilization of the recombinant gametes by homozygous recessive games from the double-mutant parent

#6 identify a 5' S 3' sequence of nucleotides in the DNA template strand for an mRNA coding for the polypeptide sequence Phe-Pro-Lys

d; 5'-CTTCGGGAA-3'...

#2 Which of the following is not true of a codon

d; it extends from one end of a tRNA molecule

When chromosomes break, two of the possible outcomes are duplications and deletions. Explain

deletion: when a chromosomal fragment is lost duplications: the "deleted" fragment may become attached as an extra segment to a sister chromatid

What is a karotype?

display of chromosomes in micrographs, arranged in pairs, starting with the longest chromosomes

#7 Which of the following mutations would be most likely to have a harmful effect on an organism

e; a single nucleotide insertion downstream of, and close to the start of the coding sequence ...

What is meant when it is said that the replication of DNA is semi conservative?

each of the two daughter molecules will have one old strand, from the parental molecule, and one newly made strand

law of independent assortment.

each pair of alleles separate from each other during gamete formation in meiosis; genes for two characters are located on different pairs of homologous chromosomes, the gamete inherits a maternal or paternal set

#10 The table shows the base composition of DNA in several species. Explain how these data demonstrate Chargaff's rules

each species DNA has a slightly different percentage of a given base. EX: % of A ranges from 24.7% foe E.Coli to 32.8% for sea urchin. It demonstrates Chargaff's rules that the DNA of different species varies in its bas of e composition. The other rule states that in any given species, the % of A is roughly equal to that of T and the % of C is roughly equal to that of G

What is DNA polymerase?

enzymes that catalyzes the synthesis of new DNA by adding nucleotides to a preexisting chain

How does the alternation of meiosis and fertilization in the life cycles of sexually reproducing organism maintain the normal chromosome count for each species?

fertilization restores the diploid chromosome count

zygote

fertilized egg

Give and example of a Y linked gene

formation of testes

If a human cell isn't a somatic cell, what type of cell is it?

gametes

What is the result of alternative RNA splicing

genes that give rise to two or more different polypeptides, depending on which segments are treated as exons duriing RNA processing ex: sex differences in fruit flies are largely die to differences in how males and females splice the RNA transcribed from certain genes

What is a gene

hereditary units that are coded with information

synapsis

holding of homolog pairs

Describe the life cycle of mammals, including humans. (haploid gametes, meiosis, fertilization, zygote)

human life cycle: Gametes are formed through meiosis where the chromosomes are reduced from two sets to one. haploid gamet (sperm) from the father fuses with a haploid gamet (egg) from the mother, forming a diploid zygote (fertilized egg). As the human develops into an adult mitosis of the zygote (division of the chromosomes) become all of the somatic cells in the body

What types of bonds hold base pairs together?

hydrogen bonds

What is the difference between incomplete dominance and codominance?

in incomplete dominance neither allele is completely dominant and the f1 hybrids have a phenotype somewhere between the those of the two parental varieties such as when a red snapdragon is crossed with a white snapdragon and the hybrids have pink flowers. In co dominance both affect the phenotype in separable distinguishable ways.

List the three events in sexual reproduction that contribute to genetic variation in a population

independent assortment of chromosomes, crossing over, and random fertilization

DNA is said to have proofreading capability. What does this mean?

initial pairing errors between incoming nucleotides and those in the template strand are 100,000 times more common - an errors rate of one in 10^5 nucleotides. During DNA replication, DNA polymerases proofread each nucleotide against its template as soon as it is added to the growing strand, it removes the nucleotide and then resumes synthesis

"filial"

latin word for son

How does the sequence of an mRNA compare to template and coding strands

mRNA sequence has 300 nucleotides to code for the 100 amino acids in a polypeptide

Why are males affected much more often than females by x linked disorders?

males have only one locus , any male receiving the recessive allele from his mother will express the trait

pleion

more

Which of the following are demonstrated by the inheritance patterns of the ABO blood group alleles: complete dominance, incomplete dominance, codominance, multiple alleles.

multiple alleles because this single gene has more than two alleles (IA, IB, i). Two of the alleles, IA and IB exhibit codominance since both carbs (A and B) present when these two alleles exist together in genotype. IA and IB each exhibit complete dominance over the i allele. This situation is not an example of incomplete dominance because each allele affects the phenotype in a distinguishable way, so the result is not intermediate between the two phenotypes. Because this situation involves a single gene it is not an example of epistasis or polygenic inheritance

What is the original source of variation among the different alleles of a gene

mutations in a gene lead to the different versions (alleles) of that gene

What is the haploid number of this cell? fig. 13.4

n=3

What is meant by calling an individual a "carrier"

offspring that inherits the recessive allele

What was Mendels experimental organism

pea plants

what is a mutagen

physical and chemical agents that interact with DNA in ways that cause mutations.

latin word for locus

place

17.1 #1 in a research article about alkaptonuria published in 1902, Garrod suggested that humans inherit two characters for a particular enzyme and that both parents must contribute a faulty version for the offspring to have the disorder. Today, would this disorder be called dominant or recessive

recessive

consanguineous

same blood "con" shared "sanguis" blood

#16 You have seen that crossing over, or recombination, is thought to be evolutionarily advantageous because it continually shuffles genetic alleles into novel combinations, allowing evolutionary processes to occur. Until recently, it was thought that the genes on the Y chromosome might degenerate because they lack homologous genes on the X chromosome with which to recombine. However, when the Y chromosome was sequenced, eight large regions were found to be internally homologous to each other, and quite a few of the 78 genes represent duplicates. (y chromosome researcher David Page has called it a "hall of mirrors") What might be a benefit of these regions

since male organs are found on the Y chromosome, extra copies of the genes might help ensure that proper formation is successful

What is the difference between a small-scale and a large scale mutation?

small scale mutations within a gene can be divided into two categories (single nucleotide-pair substitutions and nucleotide pair insertions or deletions) Large scale mutations can occur within chromosomes ..

epistasis

standing upon

What is the result of each of the following: substitution mutation frameshift mutation nonsense mutation

substitution mutations can cause missense or nonsense mutations (the altered codon still codes for an amino acid and this makes sense, although not necessarily the right sense) Frame shift mutations (occurs whenever the number of nucleotides inserted or deleted is not a multiple of three. The result is extensive missense, usually ending sooner or later in nonsense and premature termination

describe the structure of DNA. Which bases make "complementary" pairs?

sugar-phosphate backbones are the ribbons, the ribbons or strands are held together by hydrogen bonds between pairs of nitrogenous bases Adenine and Thymine compliment each other, Cytosine and guanine compliment each other

Describe the roles of the following in protein synthesis: tRNA, aminoacyl-tRNA synthetase, anticodon, ribosome

tRNA: transfers amino acids from the cytoplasmic pool of amino acids to a growing polypeptide in a ribosome. Aminoacyl-tRNA synthetase: the family of related enzymes carries out the matching of tRNA and amino acid Anticodon:a nucleotide triplet on an end of a tRNA molecule, the molecule is move through a ribosome that joins the amino acids into a chain

17.1 #3 The template strand of a gene contains the sequence 3'-TTCAGTCGT-5'. Draw the nontemplate sequence and the mRNA sequence, indicating 5' and 3' ends of each. Compare the two sequences

template sequence 3'-TTCAGTCGT-5' Nontemplate sequence 5' - AAGTCAGCA-3' mRNA sequence 5'-AAGUCAGCA-3'

In what way does the role of environment extend Mendel's model of inheritance?

the environmental factors like exposure to weather for plants or nutrition and exercise for humans can cause a change in appearance characteristics.

crossing over

the exchange of genetic material between nonsister chromatids during prophase I of meiosis

Explain what is meant by saying the concept of a gene is universal

the genetic code applies to all organisms

15.1 CC #1 Which one of Mendel's law relates to the inheritance of alleles for a single character? Which law relates to the inheritance of alleles for two characters in a dihybrid cross

the law of segregation relates to the inheritance of alleles for a single character. The law of independed assortment of alleles relates to the inheritance of alleles for two characters.

What is a reading frame

the order of symbols in the correct groupings

chiasma

the site of the crossing over; the x-shape where crossing over occurred

What does it mean when we say that the two DNA strands in the double helix are antiparallel?

the subunits run in opposite directions

What would an end of the double helix look like if the strands were parallel

they wouldn't be uniform. If they were parallel the purines would be matched up together as would the pyrimidines, causing either too wide or too narrow of a diameter of the double helix

What did he propose was passed from parents to offspring?

traits, heritable factors

State the law of segregation in term of alleles and meiosis.

two alleles in a pair segregate (separate from each other) into different gametes during gamete formation

What is meant by the term "linked" genes

two or more alleles on the same chromosome

Meiosis involves how many cell divisions?

two; Meiosis I and Meiosis II

15.2 cc #3 Consider what you learned about dominant and recessive alleles in Concept 14.1 If a disorder were caused by a dominant x linked allele how would the inheritance pattern differ from what we see for recessive x linked disorders?

with a disorder caused by a dominant allele, there is no such thing as a "carrier", since those with the allele is sufficient to result in the disorder. All fathers who have the dominant allele will pass it along to all their daughters, who will also have the disorder. A mother who has the allele (and thus the disorder) will pass it to half of her sons and half of her daughters)

How does a zygote become an adult?

zygotes go through mitosis, which divides the cells again,multiplying them. As they develop their functions in the growing embryo become specialized.