Which of the following is a component of a chromosome?
A. Centromere
B. Gamete
C. Homologue
D. Ribose
The protein disc that holds two sister chromatids together is what collectively makes a chromosome. A gene is a segment of DNA, deoxyribonucleic acid, which transmits information from parent to offspring. A single molecule of DNA has thousands of genes. A chromosome is a rod-shaped structure that forms when a single DNA molecule and its associated proteins coil tightly before cell division.
Chromosomes have two components:
- Chromatids: two copies of each chromosome
- Centromeres: protein discs that attach the chromatids together
Human cells have 23 sets of different chromosomes. The two copies of each chromosome are called homologous chromosomes, or homologues. An offspring receives one homologue from each parent. When a cell contains two homologues of each chromosome, it is termed diploid (2n). A haploid (n) cell contains only one homologue of each chromosome. The only haploid cells humans have are the sperm and eggs cells known as gametes.
Therefore, the Correct Answer is A.
More Questions on TEAS 7 Science
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Q #1: Why did it take many years for the cell theory to be developed?
A. Advancements in microscopy took place slowly.
B. Cells were difficult to isolate for experimental analysis
C. Researchers believed a cell formed from preexisting cells
D. Scientists already proved that cells were essential for life.
Answer Explanation
Robert Hooke discovered the first cells in the mid-eighteenth century. The cell theory is a theory because it is supported by a significant number of experimental findings. The cell theory took many years to be developed because microscopes were not powerful enough to make such observations.
This theory, or in-depth explanation, about cells consists of three parts:
- All living things are composed of one or more cells.
- Cells are alive and represent the basic unit of life.
- All cells are produced from pre-existing cells.
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Q #2: Which of the following are included in the male reproductive system?
A. the penis and epididymis
B. the vas deferens and uterus
C. the penis and Fallopian tubes
D. the penis, scrotum, and cervix
Answer Explanation
The main male reproductive organs are the penis and the testicles, which are located external to the body. The penis is composed of a long shaft and a bulbous end called the glans penis. The glans penis is usually surrounded by an extension of skin called the foreskin.
The testes (analogous to the female ovaries), or testicles, are retained in a pouch of skin called the scrotum, which descends from the base of the penis. The scrotum contains nerves and blood vessels needed to support the testicles’ functions. Each testicle (or testis) produces sperm (analogous to the female ova), which are passed into a series of coiled tubules called the epididymis. The epididymis stores and nurtures sperm until they are passed into the vas deferens, a tubule that is about 30 centimeters long, extending from the testicle into the pelvis and ending at the ejaculatory duct.
The epididymis and vas deferens are supported by several accessory glands (the seminal vesicles, the prostate gland, and the Cowper glands) that produce fluid components of semen and support the sperm cells.
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Q #3: What structure plays a role in air conduction?
A. Alveolus
B. Capillary
C. Lung
D. Trachea
Answer Explanation
The primary function of the respiratory system is to provide oxygen to and remove carbon dioxide from the body. In addition to gas exchange, the respiratory system enables a person to breathe. Breathing, or inhalation, is essential to life. It is the mechanism that provides oxygen to the body. Without oxygen, cells are unable to perform their functions necessary to keep the body alive. The primary muscle of inspiration is the diaphragm. Known as the chest cavity, this dome shaped structure flattens when it contracts. The rib cage moves outward, allowing outside air to be drawn into the lungs. During relaxation, the diaphragm returns to its dome shape and the rib cage moves back to its natural position. This causes the chest cavity to push air out of the lungs.
The respiratory system can be functionally divided into two parts:
- Air-conducting portion: Air is delivered to the lungs. This region consists of the upper and lower respiratory tract—specifically, the larynx, trachea, bronchi, and bronchioles.
- Gas exchange portion: Gas exchange takes place between the air and the blood. This portion includes the lungs, alveoli, and capillaries.
