EOC Biology review-1

When the skin comes in contact with an irritant, receptors in the skin send signals to the spinal cord. The signal is then sent to the brain for processing, and the individual begins to scratch the affected area.

Which two systems are most likely interacting when a person experiences itching caused by a skin irritant

• Circulatory and excretory

• Integumentary and nervous

• Digestive and muscular

• Respiratory and lymphatic

Answer explanation

The nerves in the integumentary system (skin) sense the irritation and send the signal to the brain. The brain then sends impulses through the nervous system to scratch the itch.

Which property is shared by the cells of all living things?

• The cells contain DNA composed of adenine, thymine, guanine, and cytosine.

• The cells are surrounded by a phospholipid bilayer and a cell wall made of cellulose.

• The cells have chromosomes that are located inside a membrane-bound nucleus.

• The cells rely on mitochondria to carry out aerobic cellular respiration.

Answer explanation

All living things are made of cells, which contain DNA made of the nucleotides adenine, thymine, guanine, and cytosine.

During the cell cycle, proteins called cyclins bind to enzymes that send signals for the cell to progress through stages of cell replication. At the end of this cycle, the cyclins degrade to prevent further signaling for the cells to divide.

Uncontrolled production of cyclins will most likely result in-

• the formation of tumors

• the immediate death of the cell

• the transfer of cyclins to other cells

• the formation of haploid cells

Answer explanation

Cyclins control the progression through the cell cycle. If cyclins do not degrade, then cells will continue to go through the cell cycle, resulting in the formation of a tumor (uncontrolled cell growth.)

An illustration of how a particular DNA mutation will most likely affect the polypeptide produced is shown.

What type of mutation is illustrated?

• Insertion

• Translocation

• Substitution

• Deletion

Answer explanation

This type of mutation is a substitution because the T nucleotide in the GTA DNA triplet was replaced with a G nucleotide in the mutated DNA triplet.

Farmers spray pesticides on their plants to protect the plants from being eaten by insects. Some individual insects have a genetic mutation that makes them resistant to the toxins in the pesticides.

Which statement best describes how only a few resistant individuals resulted in the pesticide becoming ineffective?

• The resistant insects change the toxin on the plants, making it safe for others.

• The resistant insects grow larger and eat less of the plants.

• The resistant insects eat the contaminated surface and leave the rest for others

• The resistant insects are able to survive to reproduce and crate a population that is also resistant.

Answer explanation

The resistant individuals that survive the spraying of pesticide are able to reproduce. This resistance is likely due to a genetic variation that has been inherited from their parents. As the pesticide will become more prevalent in the population.

The defenses of two flightless birds that live in different habitats are shown.

How do the wings of the Gentoo penguin and the legs of the common ostrich provide and advantage in their habitat?

• Allows them to find prey

• Allows them to escape from predators

• Allows them to control their body temperature

• Allows them to be camouflaged in their environments

Answer explanation

The main function of the wings of the Gentoo penguins and the legs of the common ostrich is for locomotion, which allows the birds to escape from predators.

The flow of energy in a grassland ecosystem is shown.

Based on the diagram, which two populations best represent trophic levels that receive the LEAST amount of the total energy provided to the ecosystem by the grass.

• Crickets and sparrows

• Toads and spiders

• Rabbits and mice

• Hognose snakes and owls

Answer explanation

Using the general10% law, which states 90% of the energy is lost at each trophic level (grass being at 100%) the hognose snakes would receive 0.1% of the energy produced by the grass, and at most, the own could receive 1% of the energy produced by the grass.

The life cycle of a frog is illustrated in the diagram.

Which statement best explains how the cell cycle is important to the life cycle of the frog?

• It enables frogs to reproduce tadpoles that are clones.

• It allows frogs to grow, develop, and reproduce.

• It prevents overproduction of frog offspring.

• It ensures the best adapted frogs to survive and pass on traites to offspring.

Answer explanation

The process of the cell cycle is how living organisms produce more cells, which allow the organisms to grow, develop, and reproduce.

Which graphic organizer best compares the energy inputs of cellular respiration and photosynthesis?

Answer explanation

Light energy is captured by the pigments in leaves during photosynthesis. The light energy is converted into chemical energy in the bonds of glucose, which is made during photosynthesis. Glucose is then used during cellular respiration to make another kind of chemical energy, ATP.

Overfishing is causing the decline of fish populations, such as Eastern Atlantic bluefin tuna in the Mediterranean. Eastern Atlantic bluefin tuna are caught faster than they can reproduce.

Which statement describes the most likely effect that overfishing will have on the ecosystem?

• Overfishing makes the ecosystem more stable by increasing competition for limited resources.

• Overfishing decreases the stability of the ecosystem by disrupting food chains.

• Overfishing has no effect on ecosystem's stability because it affects one species out of many.

• Overfishing increases ecosystems stability by allowing prey populations to overproduce.

Answer explanation

Overfishing decreases the stability of the ecosystem by disrupting the food chains of other organisms within the ecosystem. This causes an imbalance in predator-prey relationships, resulting in either a decrease in certain organisms or an increase in others.