Bio Unit Exam 2

Chromosome

Very long DNA molecule in association with protein

intron

a segment of DNA or RNA molecule that does not code for proteins and interrupts the sequence of genes.

Exon

a segment of a DNA or RNA molecule containing information coding for a protein or peptide sequence.

Semiconservative

DNA is ____

S Phase

DNA synthesis occurs during _____

3 hydrogen bonds

Guanine and Cytosine are held together by ____

Gene

Segment of DNA in a chromosome

Chromatin

DNA and protein combined

Chromosome number

Sum of chromosomes in a given type of cell; humans have 46; 23 from each parent.

Diploid

2 sets of chromosomes

Autosomes

Pairs 1-22

Sex chromosomes

XX and XY

Reproduction

Produces a new generation of cells, produces new individual, part of the life cycle

Life cycle

Series of recurring events in which individuals grow, develop, maintain, and reproduce.

Mitosis

Division of somatic cells, maintains diploid chromosome number; purpose: growth, replace, repair

Meiosis

Division of germ cells; halve diploid number to haploid

Cell cycle

Lifetime of a somatic cell, varies depending on cell type

Interphase

¾th of cell cycle, G1: cell growth, S: DNA chromosomes are copied through replication, G2: preparation for mitosis.

Mitosis

¼th of cell cycle, chromosomes are sorted into sets, four phases.

Cytokinesis

Cytoplasm divides

Duplicate

Before cell division, chromosomes ____

Sister chromatids

Chromosome and its copy

Duplicated chromosomes coil and condense

During early stages of cell division, _____

Centromere

Region of attachment to the microtubule

4 stages of Mitosis

How many stages are there of mitosis?

Two new cell nuclei

Mitosis produces _____ each with a set of the parents cells

At the end of anaphase

Cytokinesis, the division of cytoplasm, begins _______

Cleavage furrow

Microfilaments (actin) pull the plasma membrane inward all around the cell; this is what pinches the cell in two

Sexual reproduction

Requires two sexes to perpetuate species, males contribute sperm, females contribute eggs

Fertilization

Combines a sperm and egg to produce the first cell of the new individuals, the zygote.

Reductional division

Reduces the number of chromosomes to a haploid number

Interphase (meiosis)

Germ cell copies DNA

Meiosis 1

Two consecutive divisions of the chromosomes

Meiosis 2

Sister chromatids split, four haploid cells form

Cytokinesis (meiosis)

The division of cytoplasm between meiosis produced daughter cells

Crossing over

Nonsister chromatids break at same places along their length

Genetic recombination

Genes may have different chemical forms, variations can be passed on to offspring

Genome

Complete set of genes (and alleles) in a certain organism

Locus

The specific location of the gene on a chromosome

Diploid cells

Two copies of each gene on pairs of homologous chromosomes.

Genotype

Inherited alleles

Phenotype

Observable functional or physical traits

Homozygous dominant

AA

Homozygous recessive

aa

Heterozygous

Aa

Homozygous condition

Identical alleles

Heterozygous condition

One dominant and one recessive, dominant overshadows expression of recessive, carrier can pass recessive allele on.

Law of segregation

Pairs of alleles separated during gamete formation (disjunction)

Probability

Measure the chance that some particular outcome will occur.

monohybrid cross

Inheritance of single gene traits

Autosomal

Traits determined by genes that are on the autosomal chromosomes

Dihybrid cross

Between individuals heterozygous for two traits yield sixteen different gamete unions

Pleiotropy

Wide ranging effect of one gene

Codominance

More than one allele of a gene is expressed

Multiple allele system

Gene has three or more alleles

Penetrance

Probability that someone who inherits an allele will have the phenotype associated with it.

Continuous variation

Populations show a range of continuous differences most evident in traits that can be measured

Alleles

They are different chemical versions of the same gene, an individual inherits 1 allele per gene from each parent, an individual with 2 different alleles for the same trait is called heterozygous, in order for an individual to express a recessive allele, they must receive two copies.

DNA

Deoxyribonucleic Acid

RNA

Ribonucleic acid

Adenine, guanine, cytosine, thymine

DNA’s nitrogen containing molecules

Adenine, guanine, cytosine, uracil

RNA’s nitrogen containing molecules

Purines

Adenine and guanine

Pyrimidines

Thymine and cytosine and uridine

Complimentary base pairing

Dictates sequence of other strand, A and T, G and C

Nucleotide sequence

In a DNA molecule that codes for specific polypeptide chain

Proteins

DNA carries info for making _____ in our body

Semiconservative replication

Newly formed strands twist back into a double helix, this process is called

Gene mutation

Small scale change in the nucleotide sequence of a gene

Transcription

DNA to RNA

Translation

RNA to protiens

Rough Endoplasmic Reticulum

Mature mRNA leaves nucleus and goes to cytoplasm or ______ for production of protein

Regulatory proteins

Speed up or halt transcription, may bind with no coding DNA sequences and affect the transcription of a neighboring gene.

Glucocorticoid

Steroid that helps fight inflammation

mRNA

Carries DNA gene information out of the nucleus to the ribosomes in the cytoplasm or RER

Codon

Three bases on mRNA at a time

Start codon

AUG, establishes the reading frame for translation

Stop Codon

UAA, UAG, UGA

tRNA

Transfer RNA decodes the mRNA, each ____ is attached to a specific amino acid

rRNA

Ribosomal RNA, component of catalytically active ribosome enzyme

Amino Acids

Proteins made of polypeptides, proteins are complex macromolecules composed of 20 different amino acids, a polypeptide is a long chain of _____, ______ have a free amino group, free carbonyl group, and a side group (R)

Peptide bonds

Amino acids are joined by _____, the carbonyl group of one amino acid is covalently attached to the amino group of the next amino acid

Uridine

RNA uses the base _____ instead of thymine

Nucleus

Transcription happens in the _____

5’-3’ prime

Nucleic acids are synthesized in the ______ direction by polymerases

tRNA

What supplies the amino acids needed for protein synthesis?

Methionine

The first amino acid when making a new protein is ______, encoded by the mRNA base sequence AUG

Centromere

Location of the chromosome for microtubule attachment

Kinetochore

Protein complex at centromere facilitating microtubule attachment

Telomere

Repetitive non-coding sequence at the end of each chromosome

Sexual traits

Traits that appear more often in one sex than the other, these genes are located on autosomes

Deletion

Spontaneous, viral, irradiation, chemical, or environmental permanent loss of genetic material

karyotype

Display of photographed chromosomes from a single body cell

alleles

Different forms of a gene.

Genes

Inherited units of information located on chromosomes

Linkage

Refers to genes physically located on the same chromosome

Independent assortment

Principle stating that genes inherited from parents are sorted into gametes in new and different combinations

Homologous

Refers to a pair of chromosomes alike in length, shape, and genes

Co-dominance

I(A) I(B)= Blood Type AB

Pleiotropy

One gene has several seemingly unrelated effects