Semester 2 Biology Final Review

Front 1

How do biotic and abiotic factors influence an ecosystem?

Back 1

Because the biotic factors of an environment are the living components of an area, they are what most affect an ecosystem. Within an ecosystem, there are populations of many different species of animals and plants. Abiotic factors are things like weather and water. This changes the environment of an ecosystem and may even affect the biotic factors in an ecosystem.

Front 2

In what ways do populations interact with other populations?

Back 2

Some populations feed on other populations. For example, a population of wolves interacts with a population of coyotes because they hunt and eat them.

Front 3

What factors affect population size?

Back 3

Abiotic factors can affect population size. This is because an increase in nitrogen can cause an overgrowth of algae. Also an organism depending on oxygen can die with a decrease of oxygen.

Front 4

What factors limit population growth?

Back 4

Both biotic and abiotic factors limit population growth. Biotic factors, such as other animals or plants, can consume a great amount of resources. That way, a different species of animals will slowly decrease in population. Also, an abiotic factor, like a large change in temperature can affect an animals’ environment and also make their population decrease.

Front 5

How has the size of the human population changed over time? What are some of the reasons for this?

Back 5

Population has increased exponentially over time. In this decade it will increase another billion. This is because of modern agriculture, sanitation and medicine. Also, birth rate has remained stable, but death rate has decreased.

Front 6

What types of human activities can affect the biosphere?

Back 6

Humans already use a lot of the world’s resources and may run them out. Also, many people are polluting and using a lot of fuels, like gases, that leak into the environment and can be harmful.

Front 7

What effects do human activities have on natural resources?

Back 7

Humans keep using natural resources and they may eventually die out. Many citizens of the US use over 300x of plastic than the average Indian citizen. This shows that we are overusing our resources.

Front 8

What is the value of biodiversity?

Back 8

Biodiversity allows us to study many types of species of both plants and animals. It creates an ecosystem so each is able to survive.

Front 9

What are the current threats to biodiversity?

Back 9

Some current threats are people. Organisms lose their habitat and the likelihood of extinctions increase.

Front 10

How did Hutton and Lyell describe geological change?

Back 10

Hutton believed that layers of rock formed very slowly and that the Earth’s terrain is in motion. Lyell said if the Earth is in motion now, it probably always was and always will be.

Front 11

According to Lamarck, how did species evolve?

Back 11

Lamarck believed that helpful traits appeared because they were needed and that organs and body parts eventually disappeared if they weren’t being used. Also, he thought that alterations in body would be passed on to offspring.

Front 12

• Describe natural selection and give an example.

Back 12

Natural selection is a mechanism for change in populations; occurs when organisms with certain variations survive, reproduce, and pass their variations to the next generation. An example is how only the bunnies with fur can survive and reproduce since the furless ones will not live long enough to pass on their genes.

Front 13

• Describe artificial selection and give an example.

Back 13

Artificial selection is the selection for reproductive success in plants and animals that is directed by humans. For example, humans took wolves into Yellowstone and chose to breed certain wolves so they could become an abundant species.

Front 14

• Describe sexual selection and give an example.

Back 14

Sexual selection is the effects of the "struggle between the individuals of one sex, generally the males, for the possession of the other sex,” as said by Darwin. An example is how in the Yellowstone video about wolves, two of the females had both wanted the same male, and later the alpha female kicked the other out of the pack.

Front 15

• What is meant by common descent?

Back 15

Common descent is how all species alive today are descended with modifications from ancestral species, uniting all organisms on Earth into a single tree of life.

Front 16

• What is meant by a species’ fitness?

Back 16

In biology, fitness means the ability to survive and reproduce in their environment.

Front 17

• How is evolution defined in genetic terms?

Back 17

Evolution is also mutation: mutations are changes to the nucleotide sequence of the genetic material of an organism

Front 18

• What is the source of all genetic variation?

Back 18

Mutation; heredity

Front 19

• What is meant by genetic isolation? What are some examples in which this can occur?

Back 19

Genetic isolation is the lack of interbreeding or little genetic mixing between organisms of the same species. This can also be the result of geographic or other forms of isolation. This may happen in an ecosystem where there are so few of a species that they cannot find a mate of their same species and are forced to mate with an animal of a different species.

Front 20

• What is the typical 2N for humans? Where would you find cells like that?

Back 20

The typical 2N for humans is 46 chromosomes. [23 pairs]

Front 21

• What is the typical 1N for humans? Where would you find cells like that?

Back 21

23 chromosomes in the sperm cells and egg cells.

Front 22

• What is the result of meiosis?

Back 22

4 genetically different haploid cells

Front 23

• What happens when crossing-over occurs?

Back 23

Homologous chromosomes pair up and exchange sections of DNA. It occurs during prophase1 of meiosis.

Front 24

• What is a karyotype?

Back 24

A karyotype is when cells are stained & photographed during mitosis when the chromosomes are visible.

Front 25

• What does DNA do?

Back 25

DNA controls cell activity and carries hereditary traits. It is made up of nucleotides and is in the shape of a double helix.

Front 26

• What is the relationship between DNA, RNA and protein?

Back 26

DNA turns to RNA during transcription and RNA turns to protein in translation. They are all part of the Central Dogma Map.

Front 27

• Genotype

Back 27

The combination of genes and or alleles in the DNA of an organism.

Front 28

• Phenotype

Back 28

The observable characteristics of an organism. Results from gene expression.

Front 29

• Codon

Back 29

a sequence of three nucleotides in the DNA or RNA. Codes for a specific amino acid.

Front 30

• Anticodon

Back 30

a group of 3 nucleotides on the transfer RNA. Pairs with the complementary codon on the mRNA during protein synthesis.

Front 31

• Gamete

Back 31

a cell containing single copies of chromosomes. It can fuse with a gamete of the opposite sex to form a zygote. Also called sex cells.

Front 32

• What are the characteristics of prokaryotes?

Back 32

No nucleus, DNA is free.

Front 33

• How do prokaryotes vary in their structure?

Back 33

Prokaryotes can be a rod (bacillus) a sphere (coccus) or a spiral (spirillum).

Front 34

• How do bacteria cause disease?

Back 34

Bacteria rely on carriers to pass the disease on, such as animals, water, or food. Also, they live in blood, skin, and membranes and sometimes within cells. They may secrete toxic substances that damage vital tissues.

Front 35

• How do viruses reproduce?

Back 35

A virus must seek out an environment that provides not only nutrients, but also the cellular machinery required for life: a virus must live in a cell to reproduce. Also, the proteins take over the cellular machinery of the cell and they aid the reproduction of the virus.

Front 36

• What happens after a virus infects a cell?

Back 36

A virus uses the building blocks and energy stored that the cell has generated for its own growth and reproduction. Then, the cell is depleted of the materials and energy it needs to repair the damage.

Front 37

• What is the composition of a virus?

Back 37

Viruses are genetic material (nucleic acid) surrounded by protein. It has no membrane, nucleus or mitochondria and cannot make nutrients. They are smaller than any cell and comprised of a protein coat surrounding its viral genetic material.

Front 38

• What is a bacteriophage?

Back 38

A bacteriophage is a virus that infects bacteria that is made primarily of protein and DNA.

Front 39

• What happens during the lytic cycle?

Back 39

Virus attaches to host cell and inserts DNA (or RNA), Viral DNA hijacks cell organelles to make parts of new viruses. New virus parts assemble and destroy host cell as they burst out.

Front 40

• What happens during the lysogenic cycle?

Back 40

Virus attaches to host cell and inserts DNA (or RNA) which is incorporated into DNA of the host. Gets copied every time the cell undergoes mitoses. Trigger sends it into Lytic cycle.

Front 41

• How do viruses cause disease?

Back 41

The protein on the outside of the virus attaches to the cell membrane of specific host cells.

Front 42

• What are pathogens?

Back 42

A pathogen is an organism capable of causing disease.

Front 43

• How do antibiotics work?

Back 43

Antibiotics are chemical compounds that either kill or inhibit the growth of bacteria (only the infecting bacteria) certain antibiotics interfere with the synthesis of the cell wall.