EOC Review Chapters 6-9

Mendel, Mendel extended, DNA/RNA and biotechnology

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Law of Segregation- member of each pair of alleles separate when gametes are formed. A gamete will receive one allele or the other. (anaphase I)

Law of Independent Assortment- pairs of alleles line up independently of one another during gamete formation (metaphase I)

Mendel’s Laws

Mutations Crossing over in prophase I Independent assortment in metaphase I Sexual recombination

Variations in DNA can cause variations in organisms phenotype. This can result in the evolution of the species as traits are selected for and against

Ways in which genetic information is varied

Homozygous dominant- GG Heterozygous- Gg Homozygous recessive- gg Genotype- GG, Gg, gg Phenotype- green, yellow Allele- alternate forms of a gene Punnett square- used to determine probability of

a trait being passed to offspring P= parents, F1= 1st generation of kids, F2= 2nd generation of kids Meiosis→Fertilization→Cleavage→Differentiation

Key Terms

Punnett Squares

Two plants are crossed, the first is heterozygous for height and has yellow seeds. The second is heterozygous for height and seed color. (Tall dominant over short, Green dominant over yellow)

Genotype of parents Ttgg X TtGg Create two monohybrid cross (TtX Tt and

ggXGg) Multiply the fraction possibilities to get your

answer

Short version to dihybrid crosses

A. 0 B. 6 C. 9 D. 12 Answer C

When an organism has more than 10 fingers or toes, it is called polydactlyism.It is a dominant trait. If two heterozygous cats mate and have a litter of 12, how many of the offspring would have more than 10 fingers or toes?

A. Both parent plants are heterozygous for flower color.

B. Both parent plants were homozygous for purple flowers.

C. One plant had white flowers and the other was heterozygous.

D. One parent was heterozygous for flower color and the other was homozygous with purple flowers.

Answer A

The allele for white flowers is recessive to purple. In a generation of pea plants, 89 produced purple flowers and 21 white flowers. Which of the following is the best conclusion you can make about the parents/

Incomplete dominance- neither trait is dominant (red and white flowers make pink)

Codominance -(both are dominant) blood type Sex linked- trait is found on the X chromsome

(males more likely to have these because they only have one X chromsome)

Polygenic- several genes code for a trait (height) Multiple Alleles- 3 or more possible alleles for a

trait (blood type/A,B,O) Barr body- one X chromsome is shut down in

each female diploid cell

Inheritance Patterns

Codominance Incomplete

Autosomal- found on chromosomes #1-22, individuals need 2 recessive alleles to have disease◦ Huntington’s unusual because caused by dominant

allele Sex linked- found on X chromosomes and

males are more likely to have disease because they only have one X chromosome

Nondisjunction- chromosomes don’t separate properly during Anaphase resulting in an extra chromsome in gamete (down syndrome)

Genetic Disorders

Karyotype- picture of all chromosomes in a cell

Autosomes (#1-22) sex chromosomes #23

Pedigree – follows a trait through a family tree

The allele for brown eyes is dominant to blue eyes. Which best explains how two brown eyed parents have a blue eyed child?

A. Each parent is carrying a recessive allele for the trait.

B. Eye color is a sex linked trait and male children could have only the allele for blue eyes.

C. Mutations after fertilization could alter gene sequences and change alleles.

D. One parent must have had only blue eyed parents.

Answer A

Review Question

Griffith proved transformation- bacteria pick of DNA from environment (mice experiment)

Griffith experiment

Hershey Chase proved DNA was genetic info

Composed of nucleotides◦ 5-C sugar (deoxyribose)◦ phosphate group◦nitrogenous base

purines = adenine and guanine pyrimidines = cytosine and

thymine

Structure of DNA

phosphate group

deoxyribose (sugar)

nitrogen-containingbase

Adenine- Thymine (uracil if RNA) Cytosine- Guanine

Base Pair Rule

DNA Replication- process by which DNA makes a copy of itself in order to produce two identical cells

1. DNA is uncoiled with enzymes 2. DNA polymerase- enzyme which

then bonds the complementary nucleotides together

3. Each new DNA molecule has one original and one new strand (semiconservative model)

DNA Replication- Enzymes needed for every step

DNA polymerase

new strand nucleotide

All organisms use the same 4 bases (ATCG) It is the difference in order and arrangement

which results in the variety of life on earth This demonstrates an evolutionary

relationship between organisms The more shared DNA in the same order,

the more closely related two species are

Genetic Code is universal

RNA- nucleic acid which acts as a messenger between DNA and the ribosomes for protein synthesis

Central Dogma- information flows from DNA to RNA

RNA

Structure- single stranded 5-Carbon sugar (ribose) phosphate group nitrogenous base

◦ purines- adenine and guanine◦ pyrimidines- cytosine and uracil

Structure of RNA

Transcription- process by which information is transferred from DNA to RNA in sets of three nucleotides (codon)◦ Introns are cut out and stay in nucleus, exons leave ◦ messenger RNA (mRNA)- copies and carries

information out of nucleus to ribosome Translation- decoding of mRNA in order to form

proteins (assisted by transfer RNA- tRNA and ribosomal RNA - rRNA)◦ tRNA reads in sets of 3 called the anticodon◦ Amino acids are linked by peptide bonds to make

protein

Protein Synthesis

A. Only tRNA bends into specific shapes to make amino acids.

B. Only mRNA can repair specific mistakes in DNA code.

C. The tRNA is used on the ribosomes and the mRNA is used in the nucleus.

D. The mRNA brings information to the nucleus for the tRNA to use.

Answer A

Why do cells need both tRNA and mRNA?

Random changes to DNA Point mutation- one nucleotide is

substituted Frameshift mutation- insertion or deletion of

a base resulting in a shift as to how the codon is read

Mutagens- agents which can change the DNA (UV light, industrial chemicals etc.)

Mutations

A. 5 B. 4 C. 2 D. 3 Answer D

A codon is a sequence of three nucleotides that code for an amino acid. If the DNA sequence goes through transcription and translation, how many amino acids will result from this sequence?

A. Cells having the new DNA version will look or operate differently from cells with the original DNA.

Only the sections of DNA without mistakes will be used in the future so the DNA strand will shorten.

C. The DNA will be exactly like the original since only the original strand of DNA is used as a template.

D. When the new strand is used as a template the strand built from it will differ from the original DNA.

Answer D

A cell is replicating its DNA. Part of the DNA strand reads ACCGTAC. The new strand built off this section reads TGGAATG. What effect might this have when the DNA replicates in the future?

Cut desired gene and plasmid of bacteria with same restriction enzyme

Combine desired gene and plasmid together Insert recombinant plasmid into a bacteria

and allow to reproduce Evidence that it worked- bacteria shows

trait (glows, produces chemical etc)

Manipulating DNA

Gel ElectrophoresisDNA moves towards positive sideThe more bands that line up, the more closely related

Transgenic organisms- contain DNA from a different species

Production of medicine like insulin, make plants resistant to disease, pests, etc…, make livestock produce more meat, milk…, test out treatments for human diseases on other organisms

Uses of genetic engineering

A. Nucleic acids are used as the building blocks of proteins, while enzymes are used as the building blocks of phospholipids.

B. Nucleic acids contain the genetic code for protein synthesis, while enzymes catalyze chemical reactions

C. Nucleic acids inhibit biochemical reactions, while enzymes catalyze reactions

D. Nucleic acids transmit signals that begin biological processes, enzymes convert carbohydrates into lipids and proteins.

Answer C

Which of the following best explains the difference between the functions if nucleic acids and enzymes