Checkpoint 3

Recent studies have shown that the uses of green algae are boundless. First, scientists at R.I.T. used algae to synthesize biofuel, and recently scientists at Northwestern University and Argonne National have found that freshwater algae can remove strontium 90 from radioactive wastewater. These developments can signifi cantly aid the future effort to clean up radioactive waste at the Fukushima Daichi Plant [a nuclear power plant in Japan]. Scientists discovered that the process begins when the green algae first absorb strontium, calcium and barium from water. The strontium and barium form crystals inside each algae cell. The crystals remain inside the cells, but the algae filters out and excretes calcium and other minerals that may be present. The strontium is then isolated, and thus able to be treated. Researchers are still figuring the best way to harness the algae's capabilities. Since algae doesn't differentiate between radioactive and inactive strontium (they are chemically identical), it is not known how the algae would hold up in a highly radioactive environment. But the good news is that they have been able to manipulate the algae's process to be more strontium-selective, thus removing as much as possible.... Source: http://inhabitat.com/green-algae-could-help-clean-up-radioactive-nuclear-waste/algae-ed01/ (Links to an external site.)Links to an external site. It can be inferred from this article that

Bioaccumulation in green algae is a first step in removing contaminants from water sources

Mutations cause many disorders in humans. Cystic fibrosis (CF) is a disorder that can be passed on from generation to generation. Skin cancer is a disorder that sometimes originates in skin cells as a result of overexposure to the Sun. Which statement best explains the formation of the mutations that cause both cystic fibrosis and skin cancer?

Both of these mutations are a result of the incorrect synthesis of the proteins that make up DNA

Human genetic material is represented in the diagram below (diagram of one chromosomes with stripes and arrow pointing to one of the stripes, labeling it 'A') The region labeled A is made up of a section of

DNA that may direct protein synthesis

Researchers recently discovered that when hammerhead sharks were moved to shallower water, resulting in exposure to increased light intensity, their backs turned a deep brownish black. Which statement best supports this observation?

Genes are inherited, but their expression can be modified by interactions with the environment

Car manufacturers have begun to explore the use of biofuels, such as biodiesel, ethanol, and cooking oils made from plant material. The desired outcome of using these biofuels would be

a decrease in the use of fossil fuels

The diagram below represents a microscopic structure observed during mitosis (diagram of one chromosomes with stripes and arrow pointing to one of the stripes, labeling it 'A') The region indicated by letter A is known as

a gene

Bacteria and humans are similar in that they both

contain genetic material in the form of nucleic acids

The diagram represents a process used to modify bacterial cells (diagram of bacterial DNA being cut (step X) and foreign DNA being inserted (step Y)) In the diagram, arrows labeled X and Y represent the use of

enzymes

A normal sequence of DNA bases in a single human skin cell is CATGGC. If this sequence replicates in this cell and becomes GATGGC, this alteration will most likely be passed to

every cell that develops from this parent cell

Female mosquitoes spread diseases when they bite humans to obtain blood. It is only the females that do the biting. Research is being conducted to alter the DNA of male mosquitoes. These altered males could then mate with normal female mosquitoes. All of the resulting female offspring would have wing defects that prevent them from flying. One assumption from this research is that the

female offspring would be unable to bite humans, since they cannot fly

Information in segments of human DNA can be expressed by a bacterial cell as a result of

genetic engineering

Female mosquitoes spread diseases when they bite humans to obtain blood. It is only the females that do the biting. Research is being conducted to alter the DNA of male mosquitoes. These altered males could then mate with normal female mosquitoes. All of the resulting female offspring would have wing defects that prevent them from flying. The method used to alter the male mosquitoes is an example of an application of

genetic transformation

Brothers and sisters often have similar facial characteristics, such as nose shape or eye color, because they

have many of the same alleles that produce the same proteins

A technique used to alter cells is represented in the diagram below. (body cell---nucleus removed--- ------>nucleus fused with egg----cell divides--->new cells egg cell--nucleus removed-^) The genetic material contained in the nucleus of each of the new cells is most likely

identical to that in the original body cell

A tomato gene, known as the SIKLUH gene, has recently been discovered. The gene leads to the production of larger tomatoes. The gene affects fruit size by increasing cell layers and promoting extra cell divisions. In order to produce large fruit in other commercial plant species, scientists might

insert the gene into other types of plants

Some plants increase in height due to changes in specialized regions of cells in the tips of their branches. The processes that result in these changes include

mitosis, cell growth, and differentiation

For a human zygote to become an embryo, it must undergo

mitotic divisions

Potatoes were the main crop in Ireland in the 1800s. Almost the entire population of Ireland was dependent on a single variety of potato, the "lumper." These potatoes were reproduced by a method of asexual reproduction known as vegetative propagation. In the middle of the 1800s, a disease caused by a fungus killed almost the entire lumper crop within two years. As a result, millions of people in Ireland died of starvation. The most likely reason the potato disease was able to destroy the potato crop in such a short time is that the

potato population lacked variations

A news release about production of farm-raised salmon contains the following information: -The program is mating targeted fish to concentrate key traits in Atlantic salmon stocks. -The three-year process includes spawning, tagging, and choice of parent fish. -The fish are weighed, measured, and monitored to identify those with the best growth rates. -The project examines the performance of fish to determine which fish to use to produce the next generation. These statements indicate that the producers are attempting to improve salmon through the use of

selective breeding

The instructions for the genetic traits of an organism are directly determined by the

sequence of bases in DNA molecules

A bacterial cell begins to produce a new type of protein. This is most likely due to an alteration of the

sequence of bases in a section of a chromosome

The diagram below represents a portion of a molecule found in cells of the human body. (diagram of A with T and C with G) Sequences represented by the letters in this molecule enable human cells to

synthesize enzymes from organic molecules

The diagram below represents a technique used in some molecular biology laboratories (diagram shows a section of human DNA being places into bacterial DNA) Which phrase best describes a possible result of this process?

the production of a human protein by the bacterial cell

The diagram below represents a form of cellular reproduction (diagram of a cell dividing via mitosis) As a result of this process, offspring 1 and offspring 2 will have

the same number of genes and the same traits

Nicotine is only one of the many toxic chemicals inhaled while smoking. What effect can such toxic chemicals have on the body?

they can cause uncontrolled cell division