Bio 213 babu praveen final fall 2019

Doexyribonucleic acid (DNA)

Stores the information to make proteins, this makes life possible

Nucleotides

sugar, phosphate, nitrogenous base

Each molecule is a polymer made from 4 __________s (i.e., sugar, phosphate, and a nitrogenous base)

nucleotides

Hershey and Chase

Showed dna comprised the chemical compound of heredity

Watson and Crick

-Used Chargraff's Rules and Rosalind Franklins and Maurice Wilkins' X-Ray diffraction to proposed DNA as a right handed double helix in which the two strands are antiparellel & the bases are stacked on one another

DNA double helix

Composed of two complementary anti parallel polynucleotide strands

base pairing

Sugar phosphate backbones are held together by H-bonding or ____

complementary

Because one strand determines the sequence of the other

DNA is read

5' to 3'

An organism's genome

Is all of the genetic material in its cells; it's entire genetic complement

Chromosomes

In eukaryotes, most of the DNA is in the nucleus in discreet stretches known as _____

Genes

Functional units of sequence on these chromosomes constitute ____

Central Dogma of Molecular Biology

1950's Watson and crick describes this flow of information from nucleus acids (DNA RNA) to proteins as the _____

Transcription

DNA to RNA

Translation

RNA to protein

Messenger RNA (mRNA)

In transcription, genetic information is comprised into this in the nucleus

RNA polymerase

enzyme that links together the growing chain of RNA nucleotides during transcription using a DNA strand as a template

heterogenous nuclear RNA (hnRNA)

Preprocessed mRNA; converted to mRNA by adding a poly-A tail and 5' cap and splicing out introns

Nucleotides are always made ______ so RNA is made _____ off of the ______ DNA template strand

5' to 3'

5' to 3'

3' to 5'

Initiation

RNA polymerase binds to DNA at the gene's promoter; DNA helix unwinds; RNA synthesis begins

Elongation

DNA threaded through RNA polymerase at transcription bubble; RNA strand growing 5' to 3'; A in DNA paired with U in RNA; 30-50 nucleotides per second

Termination

RNA polymerase reaches "bumps" in terminator region and "falls off"

Polycistronic RNA

In bacterial cells, many genes are transcribed at once making this which codes for multiple proteins

Colinear

Genes and proteins are almost always this in bacteria

Messenger RNA : RNA processing

hnRNA must be modified before it is fully functional . Eukaryotic genes possess coding nucleotide sequences called introns that are transcribed but not translated into protein

Intervene between coding sequences is called

Exons

Splicing

Introns are removed from hnRNA

RNA processing is only possible in

Eukaryotic cells

Nuclear Export

So the mRNA can be translated into a polypeptide strand

Ribosomal RNA (rRNA)

A major component of the organelles (ribosomes) that construct proteins

Transfer RNA (tRNA)

Are "interpreters" that read the mRNA code; insert amino acids to the growing protein

The information to encode a single amino acid is carried in a sequence of

Three nucleotides

Each triplet is called a

Codon

The genetic code is:

degenerate

AUG is the

Start codon

The nucleic acid code in a mature mRNA is _____ into amino acids to synthesize polypeptides

translated

In eukaryotes, mature mRNA is exported out of the nucleus into the cytoplasm where it is translated by

Ribosomes

Initiation

Small and large ribosomal subunits bind mRNA; first tRNA also binds

Elongation

Ribosome catalyzes the formation of a peptide bond between the amino acid in the peptidyl site (P site) and the amino acyl site (A site)

Translocation

Ribosome ratchets over one codon jettisoning Emory tRNA and accommodating another amino acyl tRNA

Elongation and translocation repeat until

Termination

Termination

Elongation ceases once a STOP codon is reached (UAA, UAG, UGA) release factors bind the ribosome and the complex falls off

gene expression

The flow of information is highly regulated

Mutations can involve

Substitutions, insertions, or deletions of one or more nucleotides in a DNA molecule

nucleotide substitution

Mutations alter the sequence, but not the number of nucleotides in a gene

Frameshift mutations

Result from the insertion or deletion of bases

Mutations can alter polypeptide folding causing genetic disorders like

Alzheimer's disease and cystic fibrosis

Protein refolding diseases are called

prion diseases

Prions are

Protein folded into an infectious conformation that is the cause of several disorders

Cell division is essential and produces a continuous supply of

Replacement cells

asexual reproduction

Most straightforward and ancient

sexual reproduction

Offspring's genetic makeup is derived from two parents

Gamete

Sex cell

Upon fertilization

A zygote forms, grows, and divides mitotically or "clones" itself into the trillions of cells on our body

cell division

Meiosis to create unique gametes; mitosis to simply regenerate a cell

Meiosis and mitosis both require

DNA to be replicated first

Apoptosis

Programmed cell death

DNA is replicated

Semi-conservatively

Helicases unwind DNA at

Origins of replication

DNA polymerase

Builds new DNA (5' to 3') off of each template strand

Ligases

Seal up adjacent DNA molecules

In prokaryotes , asexual reproduction occurs by

Binary fission

Chromosomes are made of

Chromatin (DNA + histone proteins)

Chromatin is wound up tight into fibers of

nucleosomes

After replication and only before division do

Chromosomes condense

Condensed replicated chromosomes have two

Sister chromatids and a viable centromere

(2n)

Diploid

Diploid (humans)

We have two copies of each chromosome

Humans have ____ chromosomes

_____ autosomes

______ pair(s) of sex chromosomes

23

22

1

Two members of a pair make up a

Homologous pair of chromosomes

Homologous because they contain the same genes, but may have different

Alleles or "flavors" of the same gene

cell cycle

The sequence of events between divisions

Interphase

The time between divisions ; cell growth and DNA replication

Mitosis

Division of the chromosomes

Cytokinesis

Division of the cytoplasm; splitting into 2 cells

G1 ( Gap 1)

RNA, proteins and other molecules are made

S (synthesis)

DNA is replicated

G2 (gap 2)

Preparing for cell division

Mitosis or "M Phase" occurs in six arbitrary phases

Prophase, (Prometaphase), Metaphase, Anaphase, Telophase, Cytokinesis

Prophase/prometaphase

Chromosomes condense into two longitudinal strands or chromatids; nuclear envelope breaks down; spindle fibers (microtubules) attach

Chromatid strands are held together by a

Centromere

Because chromosomes were replicated during interphase, similar chromatids are joined at a centromere, forming ___

Sister chromatids

Metaphase

Chromosomes with spindle fibers attached to their centromeres move to the middle of the cell (the metaphase plate or spindle equator)

Anaphase

Centromeres divide to convert each sister chromatid into a chromosome

Telophase

Chromosomes reach opposite ends of the cell and decondense; nuclear envelopes reform; cells starts to take shape

Cytokinesis

Cleavage furrow forms, deepens, and cytoplasm divided to yield two daughter cells

Mitosis describes what is happening in

Somatic cells

Meiosis I'm germ cells is

The form of cell division that yields gametes

Members of a chromosome pair separate from each other so the gametes produced are

Haploid (n)

Fertilization

Is the fusion of gametes and restores the number of chromosomes back to 23 pairs, 46 total (2n)

Fertilized egg is a diploid (2n) ___ and can develop properly

Zygote

In meiosis, diploid cells (2n) undergo replication and then two rounds of division yielding

Haploid (n) gametes

Chromosomes associate into

Homologous pairs

Crossover events can occur via ______________.

Homologous recombination

Both orientation that chromosomes line up in

Increase genetic diversity in offspring

After telophase 1 / interkinesis all chromosomes are still in a duplicated state but

Cells are haploid (n)

Meiosis increases genetic diversity via (1)

Crossing over during prophase 1

Meiosis increases genetic diversity via (2)

Independent assortment during metaphase 1

Meiosis increases genetic diversity via (3)

Random fertilization

One couple could create more than _____ genetically unique individualls

70 trillion