SBP FINAL EXAM

DNA

deoxyribonucleic acid

Double Helix

a ladder-like structure that DNA consists of two molecules that are arranged into

Nucleotide

millions of tiny subunits called Nucleotides that a molecule of DNA is made up of

Nucleotide components

1. Phosphate group 2. Pentose sugar 3. Nitrogenous base

DNA backbone

The phosphate and sugar form the backbone of the DNA molecule

DNA "rungs"

the bases form the “rungs”

Four types of nitrogenous bases

Adenine, Thymine, Cytosine, Guanine

Complementary base pairing

Each base will only bond with one other specific base

Adenine (A) pairs with

Thymine (T)

Cytosine (C) pairs with

Guanine (G)

PURINES

Adenine and Guanine. They have a TWO ring structure.

PYRIMIDINES

Thymine and Cytosine. Which have a ONE ring structure.

Pairing rule

A TWO ring purine always pairs with a ONE ring pyrimidine.

Genetic code

the sequence of bases

Codons

The bases are arranged in triplets called codons.

Gene

a section of DNA that codes for a protein

Phenotype

a unique phenotype that is give by these proteins and combination of proteins

DNA Replication

Before the cell can divide it first makes a copy of its chromosomes through DNA replication

Helicase

UNZIPS DNA by breaking weak H-bonds between Nitrogen bases

Single Strand Binding Protein (SSB)

stabilizes the strands and prevents the separated strands from rejoining

DNA Polymerase

brings in new nucleotides; bonds new nucleotide to chain

Semi-conservative replication

the two new strands of DNA each contain one of the original parental strands

Primase

attaches a short sequence of RNA called a primer

RNA primer

a short sequence of RNA that primase attaches

Leading strand

the polymerase moves along the strand in the same direction as the replication fork

Lagging strand

the other strand that runs in the opposite direction

Okazaki fragments

the complementary strand to the lagging strand is made in short sections called Okazaki fragments

DNA Ligase

the enzyme that joins Okazaki fragments together

RNAse H

the enzyme that removes the primers

Protein synthesis involves two processes

transcription and translation

Transcription

the DNA message is converted into an RNA molecule

Translation

the RNA message is used to assemble amino acids into a protein chain

RNA

nucleic acid that differs from DNA in 3 ways

RNA vs. DNA 1

Single stranded vs. double stranded

RNA vs. DNA 2

Ribose sugar vs. deoxyribose

RNA vs. DNA 3

Contains URACIL(U) vs. thymine (T)

Messenger RNA (mRNA)

Long strands of RNA nucleotides that are formed complementary to one strand of DNA

Ribosomal RNA (rRNA)

Associates with proteins to form ribosomes in the cytoplasm

Transfer RNA (tRNA)

Smaller segments of RNA nucleotides that transport amino acids to the ribosome

Codon

The three-base code in DNA or mRNA is called a codon.

Anticodon

there is a three-base coding sequence in the tRNA called the anticodon.

Introns

the ‘junk’ sequences that are removed from the message

Exons

the remaining sequences that are linked together to produce a sequence of codons

Incomplete dominance

Pattern of heredity in which one allele is not completely dominant over another

Codominance

Pattern of heredity in which both alleles are simultaneously expressed in the heterozygote

Multiple alleles

A gene that is controlled by more than two alleles

Pleiotropy

When one gene affects multiple characteristics

Lethal allele

Allele that results in the death of an individual

Polygenic trait

Traits that are controlled by multiple genes

Non-Mendelian inheritance

a general term that refers to any pattern of inheritance in which traits do not segregate in accordance with Mendel’s laws

Linkage

This type of coexistence of two or more genes in the same chromosome is known as linkage.

ABO blood system

Controlled by a tri-allelic gene

Allele I^A

produces antigen A

Allele I^B

produces antigen B

Allele i

produces no antigen

ABO rule 1

A and B are co-dominant (Both show)

ABO rule 2

A and B are both dominant over O (Regular dom/rec)

Antigens

Red blood cell surface molecules. Proteins that elicit immune response.

Antibodies

Proteins carried in plasma. Protects the body from invaders.

Agglutination

Clumping of red blood cells

Rh factor

the presence or absence of a protein on the surface of the RBC

Rh positive

If you carry this protein, you are Rh positive

Rh negative

If you don't carry the protein, you are Rh negative

Monohybrid Crosses

Reveal the Principle of Segregation and the Concept of Dominance

Dihybrid Crosses

Reveal the Principle of Independent Assortment

Principle of Segregation

(Revealed by Monohybrid Crosses)

Concept of Dominance

(Revealed by Monohybrid Crosses)

Principle of Independent Assortment

(Revealed by Dihybrid Crosses)

Testcross

(Listed as a topic)

Incomplete Dominance

(Listed as a topic)

Ratios in Simple Crosses

(Listed as a topic)

Nondisjunction

happens when a chromosome pair doesn’t separate during meiosis

Aneuploidy

Biologists call this aneuploidy when a person has too many or too few genes/chromosomes.

Trisomy

People with trisomies have three copies of a particular chromosome (instead of two)

Trisomy 21

is a fairly common aneuploidy that involves an extra chromosome 21. This is also called Down syndrome.

Trisomy 13

Patau syndrome

Trisomy 18

Edward's syndrome

Klinefelter syndrome

occurs when males have an extra X chromosome

Klinefelter syndrome karyotype

47,XXY

Turner Syndrome

a chromosomal condition related to X chromosome that alters development in females

Turner Syndrome karyotype

45,XO

Intracytoplasmic sperm injection (ICSI)

fertility treatment for minimal sperm production patient where sperm is injected directly into the egg.