The two most abundant types of white blood cells may both be involved in a response to which of these?

The fact that a strain of yeast with a certain defective gene can use the human version of the gene to repair itself is evidence that yeast and humans-

7. What two human systems work together to provide body cells with a constant supply of oxygen while removing carbon dioxide waste products?

Which diagram best represents the levels of organization in the human body?

During the final stages of human gestation, receptors for the hormone oxytocin increase on the smooth muscle cells of the uterus. The release of oxytocin during labor stimulates the smooth muscle tissue in the wall of the uterus. The vigorous contraction of the uterine smooth muscle helps push the baby through the birth canal so that delivery can occur. This process involves the interaction of which organ systems?

Coracias garrulus is a blue bird with an orange-brown back. The offspring of this bird have an effective defense mechanism. The young birds vomit and cover themselves in a foul-smelling orange liquid when they sense a threat by predators. Which two systems alert the young bird to the

danger and help produce the vomit it uses as a defense?

Human bone, muscle, and nerve cells all contain the same number of chromosomes with the same complement of genes. What enables these cells to perform specialized activities?

A segment of DNA is represented in the illustration

How is information for a specific protein carried on the DNA molecule?

Inversions in chromosomes occur when part of a chromosome breaks out and is reinserted upside down. Which of the diagrams below represents an inversion?

Which phase of mitosis Is occurring in the cell indicated by the arrow?

Nitrogenous bases are located on both strands of the DNA double helix. What is the significance of the nitrogenous bases?

Part of an important cellular process involving a DNA strand is modeled below.

What is the purpose of this cellular process?

Cells pass through a G2 checkpoint before entering mitosis. Ideally, if DNA damage is detected, the cells do not enter mitosis until the damage is repaired. Why is DNA damage repaired before cells enter mitosis?

Which of the following functions at the same organizational level as the kidney in the human excretory system?

Which of the following diagrams best represents the stage of mitosis known as metaphase?

In 1952 Rosalind Franklin took the x-ray photograph shown below, which gave the world its first look at DNA.

By studying this photograph, scientists gained knowledge about the

In the 1960s the molecular biologist George Streisinger developed the strand-slippage hypothesis. Streisinger noticed that mutations occurred in areas of DNA that contained many repeated sequences. When a strand-slippage error occurs, an insertion mutation can result. How does the insertion mutation affect the DNA?

Sickle-shaped red blood cells result from a mutation in The gene that codes for hemoglobin. This mutation results in sickle-cell anemia. A partial sequence of bases from a normal hemoglobin gene and a sequence that results in sickle-cell anemia are shown below.

What type of mutation is depicted in this sequence

As a fertilized egg divides, the cells differentiate because they —

A model of a DNA molecule is shown below.

The arrow indicates —