Unit 4 Review (Genetics & DNA)

homozygous dominant

Both alleles (factors) for a trait are the same and dominant (AA)

homozygous recessive

Both alleles (factors) for a trait are the same and recessive (aa)

allele

An alternative form of a gene.

Gregor Mendel (1822-1884)

investigated inheritance in pea plants by observing differences in various traits of the plants from generation to generation, leading to the idea that information needed to build an organism is packaged into units associated with specific traits; father of genetics

Punnett Square

A chart that shows all the possible combinations of alleles that can result from a genetic cross

colorblindness and hemophilia

examples of sex-linked traits

Genotype

An organism's genetic makeup, or allele combinations.

Phenotype

An organism's physical appearance, or visible traits.

incomplete dominance

Situation in which one allele is not completely dominant over another allele

Codominance

A condition in which both alleles for a gene are fully expressed

sex-linked traits

Traits controlled by genes located on sex chromosomes.

Genetics

The scientific study of heredity; branch of Biology that studies genes, traits, & patterns of traits.

Blood Types:

Genotypes & Phenotypes

Type A = IAIA or IAi

Type B = IBIB or IBi

Type AB = IAIB

Type O = ii

Down Syndrome (Trisomy 21)

a genetic disorder caused by a trisomy of the twenty-first chromosome

DNA

A complex molecule containing the genetic information that makes up the chromosomes. It is in the form of a double helix.

4 nitrogenous bases found in DNA

Adenine (A)

Thymine (T)

Cytosine (C)

Guanine (G)

Differences between DNA and RNA

DNA has deoxyribose, thymine, and is double-stranded. RNA has ribose, uracil, and is single-stranded

Nucleotide

monomer of nucleic acids made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base

complementary strand of DNA

matching strand

Original DNA Strand "A-T-T-C-G-G-A-C-T"

Complementary DNA Strand "T-A-A-G-C-C-T-G-A"

DNA replication takes place in the ______ of the cell.

nucleus

Where does transcription take place in the cell?

nucleus

Watson and Crick

Developed the double helix model of DNA.

Make the corresponding mRNA from this DNA: TACGTTCAG

mRNA: AUG/CAA/GUG

What is the anticodon for this codon: AUG

Anti-codon: UAC

DNA is unzipped by the enzyme....

helicase

Which organelle is responsible for translation?

ribosome

Proteins are made up of....

amino acids

What is the order of processes that makes a protein?

DNA --> mRNA --> tRNA --> Amino Acid

gene

A segment of DNA on a chromosome that codes for a specific trait

During gel electrophoresis, the DNA fragments migrate from the ________ pole to the __________ pole.

negative; positive

During gel electrophoresis, __________ segments travel farther.

smaller

PCR (polymerase chain reaction)

technique that allows molecular biologists to make many copies of a particular gene (will produce millions of copies of DNA)

The enzyme used during transcription is.....

RNA polymerase

rRNA (ribosomal RNA)

type of RNA that makes up the major part of ribosomes

Meiosis makes these types of cells....

gametes (or sex cells)

At the end of meiosis, the result would be

4 haploid (only 1 set of chromosomes) cells; unique cells

Metaphase I (Meiosis)

Tetrads are lined up at the metaphase plate; Spindle fibers attach

Anaphase I (Meiosis)

Homologous chromosomes separate

Metaphase II (Stage 7)

single file chromosomes line up at the equator (very similar to mitosis)

Anaphase II (Stage 8)

The spindles pull the sister chromatids apart. Each goes towards a different pole.

What enzyme does transcription require?

RNA polymerase

What is the relationship between a protein, the cell, and DNA?

DNA controls the production of protein in the cell.