domingo, 29 de noviembre de 2009

Guia para 1° de SECUNDARIA, 2° examen bimestral de Biología (Science explorer). PARTE 1

Guide 2nd bimonthly exam. Part 1

1- What are some patterns of inheritance in humans?
Some human traits are controlled by single genes with two alleles and others by single genes with multiple alleles. Still other traits are controlled by many genes that act together.

2- What are the functions of sex the chromosomes?
The sex chromosomes carry genes that determine whether a person is male o female. They also carry genes that determine other traits.

3- What are two major causes of genetic disorders in human?
Some genetic disorders are causes by mutations in the DNA of genes. Other disorders are caused by changes in the overall structure or number of chromosomes.

4- How do geneticists trace the inherence of traits?
One important tool that geneticist use to trace the inheritance of traits in humans is a pedigree

5- How are genetic disorders diagnosed and treated?
Today doctors use tools such as karyotypes to help detect genetic disorders. People with genetic disorders are helped through medical care, education, job training and other methods.

6- What are three ways of producing organisms with desired traits?
Selective breeding, cloning and genetic engineering are three methods for developing organisms with desirable traits.

7- What is the goal of human genome project?
The main goal of human genome project has been to identify the DNA sequence of every gene in the human genome.

8- In which organelle of the cell are proteins manufactured?
One the ribosome’s in the cytoplasm of a cell.

9- What hypothesis did Darwin make to explain the differences between similar species?
Darwin reasons that plants or animals that arrived on the Galapagos Islands faced conditions that were different from those on the mainland. Perhaps, Darwin hypothesized; the species gradually change over many generations and become better adapted to the new conditions.

10- What evidence supports theory of evolution?
Fossils, patterns of early development and similarities body structures all provide evidence that organisms have changed over time.

11- How do scientists infer evolutionary relationships among organisms?
Scientists have combined the evidence of DNA, protein structure, fossils, early development and body structure to determine the evolutionary relationships among species.

12- How do new species form?
A new species can form when a group of individuals remains insolated from the rest of its species long enough to evolve different traits.

13- Homologus structures: Body parts that are structurally similar in related species and that provide the evidence of a common ancestor

14- Branching tree: A diagram that shows how scientists think different groups of the organisms are related.

15- How do most fossils from?
When organisms that die become buried is sediments.

16- How can scientists determine a fossil’s age?
Scientist can determine a fossil’s age I two ways: in relative dating and radioactive acting.

17- What is the Geologic Time Scale?
The calendar of earth´s history is some times called the Geologic Time Scale.

18- What are some un answered questions, about evolution?
Two unanswered questions about evolution involve mass extinctions and the rate at which evolutions occurs.

19- How are viruses like organisms?
That they can multiple.

20- What is the structure of a virus?
All viruses have two basic parts: an outer coat that protects the virus and an inner code made of genetic material.

21- How do viruses multiply?
Once inside the cell the Virus gene material takes over many of the cells functions. The genetic material instructs the cell to produce the virus´s proteins and genetic material, these protein and genetic material then assemble into a new viruses.

22- How can you treat a viral disease?
Resting-drinking plenty of fluids, and eating well balanced meals maybe all you can do while you recover from a viral disease.

23- How do the cells of bacteria differ from those of eukaryotes?
Bacteria are prokaryotes. The genetic material in their cells in not contained in nucleus.

24- What do bacteria need to survive?
Bacteria must have source of food and a way of breaking down the food to release energy.

25- Under what conditions do bacteria thrive and reproduce?
When bacteria have plenty of food, the right temperature, and other suitable conditions, they thrive and reproduce frequently.

26- What positive roles do bacteria play in people´s live?
Bacteria are involved in oxygen and food production, environmental recycling and cleanup and in health maintenance and medicine production.

27- What are the characteristics of animal-like, plant-like and fungus-like protists?
Animal like protists are heterotrophs and most are able to move from place to obtain food, in plant-like protists, algae are autotrophs and in fungus-like protists are heterotrophs, have a cell walls, and use spores to reproduce.

28- What characteristic do fungi share?
Fungi are eukaryotes that have a cell walls, are heterotrophs that feed by absorbing their food, and use spores to reproduce.

29- How do fungi reproduce?
Fungi usually reproduce by making spores. These spores are surrounded by a protective covering and can be carried easily through air or water to new sites.

30- What roles do fungi play in the nature?
Many fungi provide food for people and play important roles as decomposers and recycle on earth. Some fungi cause disease and others can use in health maintenance and medicine production.

31- Key Terms
Virus= A tiny, nonliving particle that invades and then reproduces inside a living cell.
Host= The organisms that a parasite or virus lives in or on.
Parasite= The organisms that benefits by living on or in a host in a parasitism interaction.
Vaccine= A substance used in a vaccitination that consists of weakened or killed pathogens.
Bactriophage= A virus that infects bacteria.
Fungi: a eukaryotic organism that has cell walls, uses spores to reproduce, and is the heterothrop that feeds by absolving its food.
hyphae: the branching threadlike tubes that make up the bodies of multicellular fungi.
fruiting body: the reproductive structure of a fungus that make up the bodies of multicellular fungi.
Budding: a form of asexual reproduction of yeast in which a new cell grows out of the body of a parent.
Lichen: the combination of a fungus and either an alga or an autotrophic bacteria that live together in a mutualistic relationship

key terms to define (pages 830 to 857)

Multiple alleles sex-linked gene sex chromosomes carrier genetic disorder pedigree karyotype selective breeding inbreeding
hybridization clone spore genetic engineering gene therapygenome species fossils adaptation evolution variation
scientific theory natural selection bacteria flagellum
binary fission asexual reproduction sexual reproduction conjugation
endoscope pasteurization decomposer protist protozoan
pseudopod contractile vacuole cilia symbiosis mutualism algae

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