Biology 9-10

Gregor Mendel

Who is considered “the Father of Genetics”?

Garden Peas

What did Gregor Mendel study?

Punnett Square

What is the best way to represent a monohybrid cross?

He saw a 3:1 ratio in the 3rd generation

Why did Mendel deduce that each trait has two alleles (factors)?

Law of Segregation

What was Mendel’s first law of inheritance?

The two alleles for each trait separate when gametes are formed

What does the law of segregation mean?

Masks the other allele; represented by a capital letter

What is a dominant allele and what type of letter is assigned?

Masked by the other allele; represented by a lowercase letter

What is a recessive allele and what type of letter is assigned?

Meiosis

Why does a gamete only have one allele for each trait?

The combination of alleles

What does genotype describe?

Two identical alleles for the trait

What is a homozygous genotype?

Two different alleles for the trait

What is a heterozygous genotype?

Appearance or expression of a trait

What does phenotype describe?

Phenotype

Does the term “albinism” describe a genotype or phenotype?

The phenotype ratio will be 9:3:3:1 ratio

In two-trait inheritance, how do we know if it follows Mendel’s law of independent assortment?

Multiplication rule (product rule)

How do we find the chances of two or more independent events occurring together?

Many traits and disorders are genetic

Why is Mendel’s work considered so important today?

Pedigree

What do we call a family history chart with regard to a particular genetic trait?

Find an inheritance pattern

Why do genetic counselors use pedigrees?

. Affected children can have unaffected parents

. Heterozygotes (Aa) have a normal phenotype

. Both males and females are equally affected

How can we tell if a pedigree is for an autosomal recessive disorder?

Shaded circle- affected female; shaded square- affected male

In class, how did we say the affected individual was shown on the pedigree?

25%, 1 in 4, or a quarter

With an autosomal recessive disorder, what are the chances for each child born to heterozygous parents to have the disorder?

. affected children will have at least one affected parent

. heterozygotes (Aa) have the disorder

. both males and females are equally affected

How can we tell if a pedigree is for an autosomal dominant disorder?

. “Blue skin disease” (methemoglobinemia)

. cystic fibrosis (CF)

. sickle cell disease

What were the autosomal recessive disorders we discussed in class?

. “Brittle bone disease” (osteogenesis imperfecta)

. Huntington disease

What were the autosomal dominant disorders we discussed in class?

“Brittle bone disease” (osteogenesis imperfecta)

Which autosomal dominant disorder comes with a light-blue tinted sclera?

Huntington disease

Which autosomal dominant disorder shows no symptoms until middle age?

Incomplete dominance

What do we call it when the heterozygote is intermediate between the two homozygotes (in phenotype)?

ABO Blood Groups (inheritance)

What is a common example for multiple allele traits?

Height, skin color

What were the two common examples of polygenetic inheritance we discussed in class?

Primrose

What was the example we looked at for multifactorial trait?

Epistatic interaction

When one gene overrides instruction for another gene, what is the term?

Marfan

Which syndrome is an example of pleiotropy?

Sex-linked

Which traits are inherited mother to son but affect males a lot more?

AG- adenine and guanine

Which DNA nucleotides are purines?

Double ring

Do the purines have a single ring or a double ring?

CT- cytosine and thymine

Which DNA nucleotides are pyrimidines?

Single ring

Do the pyrimidines have a single ring or a double ring?

What type of “backbone” do both DNA and RNA use?

Sugar-phosphate backbone

Ribose and Deoxyribose

Which type of sugar does RNA and DNA have?

Adenine hydrogen bonds thymine and guanine to cytosine

Why in each species, do the amounts of adenine and thymine equal each other and the amounts of guanine and cytosine equal each other?

S phase (of interphase)

When does DNA replication occur?

Helicase

How are the hydrogen bonds broken that hold the adenine to the thymine and the guanine to the cytosine?

DNA polymerase

How is the new daughter strand synthesized when DNA replicates (which enzyme)?

DNA ligase

How are any breaks in the sugar-phosphate back bone sealed?

Okazaki fragments

What are the fragments of the lagging strand named?

Thymine, it is replaced by uracil in RNA

Which type of DNA base is NOT found in RNA and with what is it replaced?

Transcription

What is it called when we use DNA as a template to make mRNA?

Messenger

In mRNA, for what does the “m” represent?

Transfer

In tRNA for what does the “t” represent?

20

How m any different types of tRNA molecules are present in the cytosol?

Translation

What is it called when amino acids are joined by tRNAs to form a polypeptide chain (which will become a protein)?

Nucleolus

Where in the cell are the subunits of ribosomes formed?

They make proteins (the sites of protein synthesis)

Why are ribosomes important?

DNA to RNA to protein

What is the central dogma of Biology?

Gene expression

What is the entire process of using information within a gene to synthesize protein?

Genetic code

What does the cell use to translate the language of DNA and RNA into the language of proteins?

AUG, Met

What is the start codon? What is produced (which amino acid)?

UGA, UAG, UAA; nothing (hydrolysis)

What are the three stop codons? What is produced?

64, 20

How many different codons are there? How many different amino acids are there?

Anti Codon

What do we call the group of 3 bases on the tRNA that is complementary to a specific mRNA codon?

mRNA binding site, 3 tRNA binding sites

Which type of binding sites does the ribosome have to synthesize proteins?

A- newly arrived tRNA brings a single amino acid

P- the tRNA attached to the growing peptide drops off the amino acids

E- the tRNA that attaches is now empty and exiting the ribosome

What happens at each of the 3 tRNA binding sites on the ribosome?

Genes

What are segments of DNA that code for proteins?

Nucleus

Where in the cell does transcription occur?

Cytosol/Cytoplasm and the rough ER

Where in the cell does translation occur?

Prokaryotes (specifically bacteria, specifically e coli)

Which type of cell has a lactose repressor which is turned off when milk is present, so the enzyme is the produced?

Both the nucleus and cytoplasm

Where are the mechanisms that regulate gene expression in eukaryotes?

Barr body

What is an example of chromatin condensation which is found in in mammalian females?

Some change (inside the cell)

What happens when a chemical signal binds to a cell membrane receptor?