Topic 3Genetics

asexual reproduction – only one parent, reproduction by mitosis or Binary fission

Biotechnology--The application of the principles of engineering and technology to the life sciences; bioengineering

body cell— (soma cell) any cell in the body that is not a sex cell

Bond--a mutual attraction between two atoms

Centriole—one of two tiny structures in an animal cell that helps form spindle fibers

Centromere—connection between two homologous chromosomes

Cytokinesis—division of the cytoplasm

Chromosome-- threadlike structure within the nucleus containing the genetic information that is passed from one generation of cells to the next

Chromatid—one side of a homologous pair of chromosomes

Clone-genetically identical organism produced by a single cell

DNA-- deoxyribonucleic acid, the hereditary material in humans and almost all other organisms

Egg-- female gamete that is haploid

Expressed—able to be seen in offspring

Gene-- sequence of DNA that codes for a protein and thus determines a trait.

genetic engineering-- process of making changes in the DNA code of living organisms

genetic recombination—recombination of genes during sexual reproductionHeredity-- the passing of traits to offspring

Cell cycle-- series of events that cells go through as they grow and divideMitosis—division of nucleus creating diploid cells

Mutation-- change in a DNA sequence that affects genetic information

Replicate— copying process by which a cell duplicates its DNA

selective breeding-- method of improving a species by allowing only those individual organisms with desired characteristics to produce the next generation

sexual reproduction-- process by which two cells from different parents unite to produce the first cell of a new organism

Sperm—male gamete that is haploid

Spindle-- fanlike microtbule structure that helps separate the chromosomes during mitosis

Subunit—parts DNA can be broken down into: Deoxyribose sugar, Phosphate, nucleic acid (A,T,G,C)All three together are called a nucleotide

Template— pattern used to make DNA, RNA, or proteins

Traits-- specific characteristic that varies from one individual to another

Hw: Do crossword puzzle as bonus points on your quiz tomorrow

Heredity and Genes

Heredity is the passing of genetic information from one generation to the next through reproduction.

The hereditary information (DNA) is organized in the form of genes located in the chromosomes of each cell.

Chromosomes are found in the cell nuclei, and contain the DNA molecules. It is the DNA molecules that carry the genetic information of the cell.

A human cell contains many thousands of genes in its nucleus, and each gene carries a separate piece of coded information

The traits inherited by an individual can be determined by one pair of genes or by several pairs of genes. A single gene pair can sometimes influence more than one trait.

Methods of Reproduction

There are two common methods of reproduction: asexual and sexual.

Asexual reproduction -- involves one parent or individual (often a single-celled organism)

Identical genetic copies are known as clones

Offspring are usually identical to the parent

all the genetic instructions (genes) come from one individual or parent.

BacteriaBinary fission– type of mitosis

Yeast, Hydra

Budding, unequal cytoplasmic division during mitosis

tubers, bulbs, runners, and grafting are types of vegetative propagation.Part of plant grows new plant

Bread Mold-- sporulation

Starfish/ Planaria– fragmentation/ regeneration(new organism grows from a piece of the organism)

Parthenogenesis--- makes diploid eggs that develop into a new organism

The division of the nucleus during the M phase of the cell cycle is called ___________________.mitosis

Interphase is divided into 3 phases1. ____________2. ____________3. ___________

G1—cell growthS –DNA replication

G2 – prep for mitosis

The 4 phases of Mitosis are:1.____________2._____________3._____________4._____________

prophase

Metaphaseanaphasetelophase

In plant cells a _______________ forms midway of the cell.

Cell plate

• Sexual reproduction-- involves two parents.Each parent produces sex cells. Sperm are the sex cells produced by the male; Egg is the sex cell produced by the female.

The offspring that results from sexual reproduction therefore receives half of its genetic information from the female parent (via the egg) and half from the male parent (via the sperm).

Chromosome Number

All organisms have different numbers of chromosomes.A body cell in an adult fruit fly has 8 chromosomes: 4 from the fruit fly's male parent, and 4 from its female parent.

These two sets of chromosomes are

A cell that contains both sets of homologous chromosomes is said to be .

diploid

homologous

The of sexually reproducing organisms contain only a single set of chromosomes, and therefore only a single set of genes. These cells are .

gametes

haploid

What happens during the process of meiosis?

Meiosis is a process of division in which the number of chromosomes per cell is cut in through the of homologous chromosomes in a diploid cell.

reduction

halfseparation

Meiosis involves divisions, and .

By the end of meiosis II, the diploid cell that entered meiosis has become 4 haploid cells.

Two meiosis I meiosis II

Meiosis I

Cells undergo a round of DNA replication, forming duplicate chromosomes.

Each chromosome pairs with its corresponding homologous chromosome to form a tetrad. Also called synapsisThere are 4 chromatids in a tetrad.

When homologous chromosomes form tetrads in meiosis I, they exchange portions of their chromatids in a process called .

crossing-over

Crossing-over produces new of alleles.

combinations

Spindle ______________ attach to the chromosomes.

The fibers pull the _________________ chromosomes toward opposite ends of the cell.

____________________ membranes form.

The cell ____________________ into two cells.

The two cells produced by meiosis I have chromosomes and alleles that are different from each other and from the diploid cell that entered meiosis I.

fibers

homologous

Nuclearseparates

Meiosis II

The two cells produced by meiosis I now enter a _____________ meiotic division.

Unlike meiosis I, neither cell goes through chromosome__________________.

Each of the cell’s chromosomes has 2 ____________________.

second

replication

chromatids

A to B Meiosis I results in two ______________(N) daughter cells, each with half the number of chromosomes as the ________________cell.

C The chromosomes line up in the ______________ of cell.

D The sister ____________________ separate and move toward ______________ ends of the cell.

E Meiosis II results in ______________ haploid (N) daughter cells

haploid

original

center

chromatidsopposite

four

Gamete FormationIn male animals, meiosis results in four equal-sized gametes called sperm.

In many ____________ animals, only one egg results from meiosis. The other three cells, called ___________ bodies, are usually not involved in reproduction.

female

polar bodies

Mitosis results in the production of two genetically identical diploid cells. Meiosis produces four genetically different haploid cells.

Mitosis •Cells produced by mitosis have the same number of chromosomes as the original cell.

•Mitosis allows an organism to grow and replace cells.

•Some organisms reproduce asexually by mitosis.

Meiosis •Cells produced by meiosis have half the number of chromosomes as the parent cell.

•These cells are genetically different from the diploid cell and from each other.

•Meiosis is how sexually reproducing organisms produce gametes.

When a sperm and egg combine to form a new cell with a complete set of genetic instructions, a unique combination of genes results. The term for this is genetic recombination.

Hw: pg 42 Questions 1-7

The Genetic CodeThe inherited instructions (genes) that are passed from parent to offspring exist in the form of a chemical code called the genetic code. It is contained in the DNA molecules of all organisms. DNA molecules resemble a flexible, twisted ladder formed from many smaller repeating units

Like other large molecules of life, the DNA molecule is made of thousands of smaller sections called subunits.

Each subunit has three chemical parts: 1. a sugar2. a phosphate3. a base.

The bases of a DNA molecule are represented by the letters

1. A 2. G3. C4. T

The four subunits of DNA molecules are arranged in pairs, each subunit forming one side and half ofone rung of the "twisted ladder."

Watson and Crick's model of DNA was a double helix, in which two strands were wound around each other.

Watson and Crick discovered that hydrogen bonds can form only between certain base pairs

• adenine and thymine

• guanine and cytosine.

This principle is called base pairing.

DNA and Chromosomes

In _________cells, DNA is located in the cytoplasm.Most prokaryotes have a __________ DNA molecule containing nearly all of the cell’s genetic information.

prokaryotic

single

Many _______________ have 1000 times the amount of DNA as prokaryotes.Eukaryotic DNA is located in the cell ____________ inside chromosomes. The number of chromosomes varies widely from one species to the next.

eukaryotic

nucleus

Eukaryotic Chromosome StructureEukaryotic chromosomes contain DNA wrapped around _______________ called histones. The strands of nucleosomes are _____________ coiled and supercoiled to form chromosomes.

proteins

tightly

What happens during DNA replication?DNA Replication

Each strand of the DNA _______________ helix has all the information needed to ___________________ the other half by the mechanism of base pairing

double

reconstruct

In most prokaryotes, DNA replication begins at a single point and continues in two directions.

In eukaryotic chromosomes, DNA replication occurs at _______________of places. Replication proceeds in ________________ directions until each chromosome is completely copied.The sites where separation and replication occur are called ________________ forks.

hundreds

Both

replication

DNA replication videoWhat happens during DNA replication?DNA Replication

Each strand of the DNA _______________ helix has all the information needed to ___________________ the other half by the mechanism of base pairing.

double

reconstruct

In most prokaryotes, DNA replication begins at a ___________ point and continues in two directions.In eukaryotic chromosomes, DNA replication occurs at _______________of places.

Single

hundreds

Replication proceeds in ________________ directions until each chromosome is completely copied.The sites where separation and replication occur are called ________________ forks.

both

replication

RNANote: no thymine, it is replaced by uracil

________ are coded DNA instructions that control the ___________ of proteins. Genetic ______________ can be decoded by copying part of the ___________ sequence from DNA into RNA. RNA contains __________ information for making proteins.

Genesproduction

messages

nucleotidecoded

The Structure of RNARNA consists of a long chain of nucleotides.Each nucleotide is made up of a 5-carbon sugar (Ribose)a phosphate groupand a nitrogenous base.

Draw this

Ribose

There are three main differences between RNA and DNA:

•The sugar in RNA is _________ instead of deoxyribose. •RNA is generally _______-stranded.•RNA contains _________ in place of thymine.

ribose

single

uracil

There are three main types of RNA:•_______________•________________•transfer RNA

Messenger RNARibosomal RNA

• Messenger RNA (mRNA) carries copies of instructions for assembling ____________ acids into proteins.

• Ribosomes are made up of proteins and ___________ RNA (rRNA).• During protein construction,

___________ RNA (tRNA) transfers each amino acid to the ribosome.

amino

ribosomal

transfer

What is transcription?

Transcription

RNA molecules are produced by __________ part of a ___________ sequence of DNA into a _______________ sequence in RNA.

This process is called transcription.

copying nucleotide

complementary

Transcription requires the __________ RNA polymerase.enzyme

During transcription, RNA polymerase binds to DNA and separates the DNA strands.

RNA polymerase then uses one strand of DNA as a template from which nucleotides are assembled into a strand of RNA.

RNA polymerase binds only to _____________ of DNA known as promoters.

____________________ are signals in DNA that indicate to the enzyme where to bind to make RNA.

http://www.youtube.com/watch?v=ztPkv7wc3yU&feature=related

regions

promoters

The Genetic Code

The genetic code is the “language” of mRNA instructions.

The code is written using four “letters” (the bases: A, U, C, and G).

A _________ consists of three consecutive nucleotides on mRNA that specify a particular amino acid.

codon

Each codon specifies a __________ amino acid that is to be placed on the polypeptide chain.

Some amino acids can be specified by more than _________ codon.

particular

one

There is one codon _______that can either specify the amino acid methionine or serve as a “start” codon for protein synthesis.

There are ________ “stop” codons that do not code for any amino acid. These “stop” codons signify the end of a polypeptide.

AUG

three

Translation is the __________ of an mRNA message into a polypeptide chain (protein).

Translation takes place on ribosomes.

During translation, the cell uses information from messenger RNA to produce proteins.

decoding

Messenger RNA is ______________ in the nucleus, and then enters the cytoplasm where it ______________ to a ribosome.

Translation begins when an mRNA molecule attaches to a ____________.

transcribed

attaches

ribosome

As each codon of the mRNA molecule moves through the_____________, the proper amino acid is brought into the ribosome by tRNA.

ribosome

In the ribosome, the ___________ is transferred to the growing polypeptide chain.

Each tRNA molecule ____________ only one kind of amino acid.

In addition to an amino acid, each tRNA molecule has ______ unpaired bases.

Amino acid

carries

three

These bases, called the ___________, are complementary to one mRNA codon.The ribosome binds new tRNA molecules and amino acids as it moves along the mRNA.The process __________ until the ribosome reaches a stop codon.

anticodon

continues

The Roles of RNA and DNA

The cell uses the DNA “master plan” to prepare RNA “_________.”

The DNA stays in the ___________.

The RNA molecules go to the ______ building sites in the cytoplasm—the ribosomes.

blueprint

nucleus

protein

Genes and Proteins

Genes contain instructions for assembling________.

Many proteins are enzymes, which catalyze and _________ chemical reactions.

proteins

regulate

Proteins are each specifically designed to build or operate a _____________ of a living cell.

The sequence of bases in DNA is used as a ______________ for mRNA.

The codons of mRNA specify the sequence of amino acids in a __________________.

component

template

protein

Do Questions 8-22, page 51 and 52 in workbook.

Classwork !!!!!!!!!!!!! This means no talking and do the work!!!! Must be done on separate answer sheet and turned in for grade.

Mutations

•Mutations are changes in the DNA _______________that affect genetic information.

sequence

•Types of gene mutations (changes in a single gene):

Substitution--__________________

–Original strand: TAC GCA TGG–Mutated strand: TAC GTA TGG

One nucleic acid is substituted for another

• Insertion—________________________

–Original strand: TAC GCA TGG

–Mutated strand: TAT CGC ATG G

One nucleic acid is added in

Deletion – ____________________________• Original strand: TAC GCA TGG• Mutated strand: TCG CAT GG

• ___insertions______and _____deletion_____cause the biggest problems because everything shifts–This is called a ___mutation_______ This makes the code unreadable

One nucleic acid is left out

Example:Normal DNA-THEREDFOXATETHEBIGRAT

Insertion mutation-THEEREDFOXATETHEBIGRAT

Deletion mutation-THEEDFOXATETHEBIGRAT

Types of chromosomal Mutations (______________________________________):

CHANGE IN WHOLE CHROMOSOME

HW DO PAGE 52 AND 53 QUESTIONS 23-31

DNA and Individuality Genes are expressed differently in organisms based on environmental conditions NATURE VS. NURTURE

Two organisms (twins) can have the same DNA, but it might show up differently due to the environment

Selective BreedingQuestion: What is the purpose of selective breeding?

Examples: Nearly all domestic ____________ and most Crop plantshave been produced by selective breeding.

animals

Selective breeding allows only those organisms with desired characteristics to produce the next generation

A) Hybridization

Hybridization is the crossing of dissimilar individuals to bring together the ________ of both organisms.

Hybrids, the individuals produced by such crosses, are often ____________ than either of the parents.

best

hardier

B) Inbreeding Inbreeding is the continued breeding of individuals with ______________ characteristics.

Inbreeding helps to ensure that the ________________ that make each breed unique will be ________________.

Warning! Serious genetic problems can result from excessive inbreeding.

similar

characteristics

preserved

Increasing VariationQuestion: Why might breeders try to induce mutations?

Answer: Breeders induce mutations to ________________ genetic variation in a population.

increase

Mutations

Mutations occur spontaneously, but breeders can increase the mutation rate by using _______________ and __________________.

Breeders can often produce a few mutants with desirable characteristics that are not found in the original population.

radiationchemicals

A) Producing New Kinds of BacteriaIntroducing mutations has allowed scientists to develop hundreds of useful bacterial strains, including bacteria that can clean up _______ ___________.Oil spills

B) Producing New Kinds of Plants

Mutations in some plant cells produce cells that have ___________ or ____________ the normal number of chromosomes.

This condition, known as _______________, produces new sof plants that are often larger and stronger than their diploid relatives.

Warning! Polyploidy in animals is usually fatal.

double triple

polyploidy

The Tools of Molecular Biology

Question: How do scientists make changes to DNA?

Answer: Scientists use their knowledge of the _______________ of DNA and its _________________ ___________________ to study and change DNA molecules.

structurechemical

properties

Scientists use different techniques to:______________ DNA from cells_________ DNA into smaller piecesidentify the sequence of bases in a DNA

moleculemake unlimited ___________ of DNA

In ___________ ________________, biologists make changes in the DNA code of a living organism.

DNA ExtractionDNA can be extracted from most cells by a simple ________________ procedure.The cells are opened and the DNA is ___________________ from the other cell parts.

Cutting DNAMost DNA molecules are too ____________ to be analyzed, so biologists cut them into smaller fragments using ____________ __________________. Each restriction enzyme cuts DNA at a specific sequence of __________.

Separating DNAIn gel electrophoresis, ______ ________________ are placed at one end of a porous gel, and an electric voltage is applied to the gel. When the power is turned on, the negatively charged DNA molecules move toward the ________ end of the gel. Gel electrophoresis can be used to _____________ the ________________ of different organisms or different individuals. It can also be used to _________ and __________ one particular gene in an individual's genome.

1) _______________ _____________ cut DNA into fragments.2) The DNA fragments are poured into ________ on a gel.3) An electric voltage is applied to the gel. This moves the ______ ______________ across the gel.The smaller the DNA fragment, the faster and farther it will move across the gel.4) Based on size, the DNA fragments make a _________ __ ___________ on the gel.5) These bands can then be ______________ with other samples of DNA.

Using the DNA Sequence

Knowing the sequence of an organism’s DNA allows researchers to study specific genes, to compare them with the genes of other organisms, and to try to discover the functions of different genes and gene combinations

Reading the SequenceIn DNA sequencing, a complementary DNA strand is made using a small proportion of fluorescently labeled nucleotides.

Each time a labeled nucleotide is added, it stops the process of replication, producing a short color-coded DNA fragment.

When the mixture of fragments is separated on a gel, the DNA sequence can be read.

Cutting and PastingGene splicing

Short sequences of DNA can be assembled using DNA synthesizers. “Synthetic” sequences can be joined to “natural” sequences using enzymes that splice DNA together.

These enzymes also make it possible to take a gene from one organism and attach it to the DNA of another organism. Such DNA molecules are sometimes called recombinant DNA.

JellycatsLemid?

Jellyfish glow gene

Making Copies

Polymerase chain reaction (PCR) is a technique that allows biologists to make copies of genes.

A biologist adds short pieces of DNA that are complementary to portions of the sequence.

1) DNA is heated to separate its two strands, then cooled to allow the primers to bind to single-stranded DNA.

2) An enzyme called DNA polymerase starts making copies of the region between the primers.