Unit 6 Review: Genetics

Vocabulary Review

Allele — alternative forms of a gene for each variation of a trait of an organism
Chromosomes-- a structure of DNA that carry genes in a linear order
Codon-- three nitrogen bases in the messenger RNA chain that codes for a specific amino acid
Crossing over — exchange of genetic material between non-sister chromatids from homologous chromosome during prophase I of meiosis; results in new allele combinations
Diploid — cell with two of each kind of chromosome; is said to contain a diploid, or 2n, number of chromosomes
Dominant — observed trait of an organism that mask the recessive form of a trait
Egg — haploid female sex cell produced by meiosis
Fertilization — fusion of male and female gametes
Gamete — male and female sex cells, sperm and eggs
Genetic recombination — major source of genetic variation among organisms caused by re-assortment or crossing over during meiosis
Genetics — branch of biology that studies heredity
Genotype — combination of genes in an organism
Haploid — cell with one of each kind of chromosome; is said to contain a haploid or n, number of chromosomes.
Heredity — passing on of characteristics from parents to offspring
Heterozygous — when there are two different alleles for a trait
Homologous chromosome — paired chromosomes with genes fro the same traits arranged in the same order.
Homozygous — when there are two identical alleles for a trait
Hybrid — offspring formed by parents having different forms of a specific trait.
Law of independent assortment — Mendelian principal stating that genes for different traits are inherited independently of each other.
Law of segregation — Mendelian principal explaining that because each plant has two different alleles, it can produce two different types of gametes. During fertilization, male and female gametes randomly pair to produce four combinations of alleles
Meiosis — type of cell division where one body cell produces for gametes, each containing half the number of chromosomes in a parent’s body.
Nucleotide- the smallest unit of DNA consisting of a phosphate, sugar and a nitrogen base
Phenotype — outward appearance of an organism, regardless of its genes.
Pollination — transfer of male pollen grains to the pistil of a flower
Recessive — trait of an organism that can be masked by the dominant form of a trait
Sexual reproduction — pattern of reproduction that involves the production of subsequent fusion of haploid cells.
Sperm — haploid male sex cells produced by meiosis
Trait — characteristic that is inherited; can be either dominant or recessive
Zygote — diploid cell formed when a sperm fertilizes an egg.

Essential Questions

1. Does environment conditions affect the expression of a gene? Remember the Himalyian Rabbit!

2. What are the "bands" on a chromosome called?

3. When can mutations in the genetic code of a parent only be transmitted to its young?

4. What is bigger: a gene, chromosome or nuclei?

5. What would happen to the amino acids coded by a DNA sequence if the DNA nitrogen base order was changed?

6. Does a mutation of a gene ALWAYS affect the phenotype of an organism?

7. What are some causes of DNA mutations?

8. How does a doctor determine if a fetus has Down syndrome?

9. What is a karyotype and what can it determine?

10. Sex linked traits such as color blindness are carried on which chromosome- the Y or X?

11. Genetic Engineering needs what kind of specific chemicals to break apart and stitch together DNA segments?

12. Does a long chain of amino acids make up a carbohydrate, protein or fat?

13. A molecule of DNA carries genetic information for what purpose?

14. Nitrogen base pairs of A matches with ______, and G with _______ in the DNA.

15. How do nitrogen base pairing change with RNA?

16. Which RNA can exist in the nucleus and the cytoplasm?

17. How do the percentage of DNA differ between identical twins, parents and children and siblings?

18. What kinds of advancements can be achieved through genetic engineering/manipulation?

19. How is selective breeding achieved and for what purpose?

20. How does selective breeding differ from natural selection?

21. Genetic Engineering is when a segment of favorable DNA is inserted into what?

22. Gel electrophoresis works because smaller DNA fragments move to which side of the machine?

23. Genetic engineering has been able to create what kinds of important hormones?

24. What is cloning?