Heredity
State Objectives 3d & 3f
___________ (Deoxyribonucleic acid)
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Chemical inside cell that contains __________________________ information
_________________________ how an organism will look & behave
Shaped like a __________________ ladder
Rungs hold ______________________ information that is a pair of bases
Reproduction
• Reproduction is the process of producing a _________________________ organisms
• The purpose is to transfer _______________________
Sexual Reproduction
• New organisms is produced from the ______________________ DNA of _____________ different cells
called sex cells.
– Male is called _______________________ & Female is called __________________________
• ___________________ occurs when an egg and sperm unite to form a new organism with half of each
parent’s DNA
• ___________________ sexually reproduce from male and female parts of a flower
• Sex cells are formed by the process of ___________________________
Meiosis
• During meiosis, the chromosome pairs ___________________ and are distributed to 4 different cells. The
resulting sex cells have only _________________________ as many chromosomes as the other cells in
the organism.
Heredity
• The _________________________ of traits from parent to offspring
• _____________________: physical characteristics of an organism
–Example: eye color, hair color, & height
Passing Traits to Offspring
• Sex cells have ___________ chromosomes and the two sex cells combine to form a zygote with 46
chromosomes
• During fertilization the offspring receives ____________ of its genetic information from its mother and the
other half from its father.
Genetics
• The _______________ of how traits are passed from parent to offspring by looking at genes
– _______________ are small sections of DNA on a chromosomes that has information about a trait
• Each ______________________ has a gene for the same trait (eye color from mom & eye color from dad)
– Traits are determined by _____________________ on the chromosomes
• Each gene of a gene pair is called an _____________________
– Inherited traits are ________________________ by the alleles on the chromosome
The DNA Code
• Chromosomes are made of _______________________________.
• Each chromosome contains thousands of genes.
• The sequence of bases in a gene forms a _______________________ that tells the cell what protein to
produce.
Genes on a Chromosome
• Chromosomes are made up of many ____________________ joined together like beads on a string.
• The chromosomes in a pair may have _____________ alleles for some genes and the same allele for
others.
Genome
• Scientists map a genome to identify all the organisms genes & figure out where they are located
– A _______________________ is the complete sequence of an organisms DNA
The Sex Chromosomes
• The __________________ chromosomes carry genes that determine whether a person is male or female.
– also carry _________________________ that determine other traits.
– _________________ = female
– _________________ = male
Types of Alleles
• _________________________ Alleles describe a genetic factor that is always expressed.
– It ________________________ a recessive trait from showing up in offspring.
– Represented by ________________________ letters (B)
• ___________________________ Alleles describe a genetic factor that is not always expressed.
– It only expresses itself when __________________ of the recessive traits are
______________________
– Represented by ______________________________ letters (b)
Examining & Studying Traits
• Two ways scientist study traits
– _________________________: outside expression of a gene
• Blue Eyes
– _______________________: the two alleles a person has inherited that can only be seen on the DNA
• BB, Bb, or bb
• Two categories of genotypes
– ___________________zygous: inherited two identical alleles
• BB (pure dominant) or bb (pure recessive)
– ___________________zygous: inherited two different alleles
• Bb (hybrid)
Punnett Squares
• Shows all possible ___________________________ of alleles that children can inherit from parents
• Mom’s genotype for brown eyes (__________)
• Dad’s genotype for brown eyes (___________)
• Offspring’s Phenotype
– 75% brown, 25% __________________
• Offspring’s Genotype
– 25% ___________, 50% Bb, 25% bb
Punnett Square Practice
• What is the genotype and the phenotype for each parent? ___________________
• What are the possible genotypes and the phenotypes for the offspring? _____________________
Co-dominance
• In co-dominance, the alleles are neither dominant nor recessive. As a result, _______________ alleles
are expressed in the offspring.
•
FW FB = black & white, FB FB = black, FW FW = white
Incomplete Dominance
• In incomplete dominance, one allele is not completely dominant over the other allele. As a result, both
alleles have a _____________________________ expression.
•
RR = red, WW = white, RW = pink
Pedigree
• Geneticist use pedigrees to ________________________ a human trait to learn how the trait was
inherited
• A _______________________ is a chart or “family tree” that tracks the members of a family that have a
certain trait.
• Circles stand for __________________________
• Squares stand for _________________________
• A line connecting a square & circle shows they are married
• Shaded = person ____________________ the trait
• Half-shaded = _________________________ one allele for the trait but does _________________have
the trait
• No shading = person does _______________________have or carry the trait
Pedigree Practice
• What does this symbol stand for? Male or female
• What does the shading of this symbol represent? _________________________
Biotechnology
• __________________________________ is the manipulation of living things to make useful products
– Causes __________________________ in an organism
• Examples of genetic biotechnology
Selective Breeding
• ___________________ Breeding is an intentional mating of organisms to produce offspring with specific
traits
• Pure breeding
– Crossing two individuals that have ________________________ or similar sets of alleles.
• Example: breeding only fast horses, breeding only labs
– Con – _____________________ genetic variety therefore makes it harder to adapt, resist diseases,
and higher chance of genetic disorders
• Hybridization
– Crossing two genetically _______________________ individuals. The Hybrid organism is bred to have
the ________________________ traits from both parents.
• Example: Labradoodles, corn produces lots of kernels with one resistant to disease
– Con – doesn’t always turn out the planned way & is time consuming
• Can ___________________ easily __________________ weather the dominant or recessive trait
will appear
Genetic Engineering
• Genetic engineering _________________________ the genetic material of a living organism by removing
genes from one organism then transferring them into the DNA of another organism. (gene splicing)
• Uses:
– Make medication and treat ______________________________
– _______________________ human genetic disorders
– Improve crops
• ________________________ were the first success with genetic engineering because they are one
celled and not as complex.
• Ex. Insert bacteria DNA into rice, wheat, and tomatoes to enable plants to survive in colder temps, poor
soil conditions, and resist insect pests.
Gene Therapy
• Gene ____________________ is an experimental technique that uses genes to treat or
________________________ disease by inserting working copies of a gene directly into the cells of a
person with a genetic disorder
• Researchers are testing several approaches to gene therapy, including:
– ___________________________ a mutated gene that causes disease with a healthy copy of the gene.
– ____________________________, or “knocking out,” a mutated gene that is functioning improperly.
– ____________________________ a new gene into the body to help fight a disease.