What organelle is only associated with plant cells?
A. Cell wall
B. Ribosome
C. Cytoplasm
D. Golgi apparatus
Only plant cells have cell walls, which help protect the cell and provide structural support. The cell wall also enforces the overall structural integrity of the plant cell, and it is found outside the cell membrane. The next organelle is a chloroplast. It is found in the cytoplasm of only plant cells. Chloroplasts are photosynthetic compounds used to make food for plant cells by harnessing energy from the sun. These organelles play a role in photosynthesis.
Therefore, the Correct Answer is A.
More Questions on TEAS 7 Science
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Q #1: Fertilization (the fusing of one sperm and an ovum) results in a(n) _____.
A. embryo
B. fetus
C. infant
D. zygote
Answer Explanation
Human intercourse consists of the male introducing sperm into the female’s reproductive system. Sperm may then pass through the female’s reproductive system to the Fallopian tubes where one sperm fertilizes an ovum, creating a zygote. The zygote passes out of the Fallopian tube and implants into the uterine wall to begin gestation. Over nine months, the zygote develops and grows into an embryo and then a fetus. An infant is the baby that is born.
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Q #2: A researcher notices a positive correlation between the height of a plant and nutrient concentration over time. Based on this observation, what conclusion does he reach?
A. The height of a plant increases in the absence and presence of the nutrients
B. When the amount of nutrients available to the plant decreases, its height increases.
C. The amount of nutrients available to a plant is independent of how tall the plant gets
D. When the amount of nutrients available to the plant increases, its height also increases.
Answer Explanation
Because this is a positive correlation, if the nutrient concentration increases or decreases, plant height will either increase or decrease accordingly.
While analyzing data, scientists tend to observe cause-and-effect relationships. These relationships can be quantified using correlations. Correlations measure the amount of linear association between two variables. There are three types of correlations:
Positive correlation:
As one variable increases, the other variable also increases. This is also known as a direct correlation.Negative correlation:
As one variable increases, the other decreases. The opposite is true if one variable decreases. A negative correlation is also known as an inverse correlation or an indirect correlation.No correlation:
There is no connection or relationship between two variables. -
Q #3: Which of the following is supported by the cell theory?
A. Cells are alive and recognized as the building blocks for life.
B. Scientists can identify and differentiate cells by using a microscope
C. Cells are produced from existing cells using meiosis instead of mitosis.
D. Living things are composed of a single cell that remains undifferentiated
Answer Explanation
After scientists were able to view cells under the microscope they formulated the cell theory. One part of this theory concluded that all cells are alive. They also represent the basic unit of life.
All living things are made of cells. Cells are the smallest structural units and basic building blocks of living things. Cells contain everything necessary to keep living things alive. Varying in size and shape, cells carry out specialized functions. 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 #4: What is the final structure through which urine must travel to empty out of the body?
A. Bladder
B. Kidney
C. Ureter
D. Urethra
Answer Explanation
The primary organ of the urinary system is the kidney. Blood from the heart flows through the kidneys via the renal artery. As blood drains from the kidney, it exits through a series of veins, the most prominent of which is the renal vein. When urine is produced, it does not drain through the tubes through which blood flows. Rather, urine flows through two ureters before emptying into the urinary bladder.
The following steps outline how the urinary system works:
- Kidney filters and excretes wastes from blood, producing urine.
- Urine flows down the ureters.
- Urine empties into the bladder and is temporarily stored.
- Bladder, when filled, empties urine out of the body via the urethra.
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Q #5: A person is diagnosed as having acidosis, a condition in which the blood pH is below 7.45. What does the doctor most likely conclude?
A. Too much carbon dioxide is found in the blood.
B. Highly oxygenated blood circulates through the body
C. A blockage prevents blood from leaving the pulmonary artery
D. The nasal cavity has a difficult time clearing particles from the air.
Answer Explanation
Acidosis is when the body fluids contain too much acid, or low pH. The kidneys and lungs are unable to keep the body’s pH in balance. Acidosis is the result when there is too much loss of bicarbonate from the blood known as metabolic acidosis, or due to a buildup of carbon dioxide in the blood due to poor lung function, known as respiratory acidosis. It is the opposite of alkalosis, which is a condition in which there is too much base in the body fluids.
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Q #6: During the aging process, not all hormone levels decrease; some actually increase. Which of the following is a hormone that may increase as a person ages?
A. Cortisol
B. Insulin
C. Luteinizing
D. Thyroid
Answer Explanation
The aging process affects hormone activity in one of three ways: their secretion can decrease, remain unchanged, or increase.
Hormones that decrease secretion include the following:
- Estrogen (in women)
- Testosterone (in men)
- Growth hormone
- Melatonin
In women, the decline in estrogen levels leads to menopause. In men, testosterone levels usually decrease gradually. Decreased levels of growth hormone may lead to decreased muscle mass and strength. Decreased melatonin levels may play an important role in the loss of normal sleep-wake cycles (circadian rhythms) with aging.
Hormones that usually remain unchanged or slightly decrease include the following:
- Cortisol
- Insulin
- Thyroid hormones
Hormones that may increase secretions levels include the following:
Parathyroid hormone
- Follicle-stimulating hormone (FSH)
- Luteinizing hormone (LH)
- Norepinephrine
- Epinephrine, in the very old
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Q #7: In which state of matter are the intermolecular forces between particles in a substance the strongest?
A. Gas
B. Liquid
C. Plasma
D. Solid
Answer Explanation
In solids, particles are usually closer together than in other states of matter because of the strong cohesive forces between the particles.
- Solids, liquids, gases, and plasmas differ from one another in the amount of energy that the particles have and the strength of the cohesive forces that hold the particles together.
- Cohesion is the tendency of particles of the same kind to stick to each other.
- A solid has the lowest amount of energy because its particles are packed close together. Liquids have more energy than a solid, and gases have more energy than solids or liquids because the cohesive forces are very weak.
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Q #8: An intracellular chemical signal can be produced in the cell membrane. Once it is produced, where does it go?
A. To a different cell
B. To another part of the same cell
C. To a region right outside the cell
D. To an area with a high ion concentration
Answer Explanation
There are two major types of receptor molecules that respond to an intercellular chemical signal:
- Intracellular receptors: These receptors are located in either the cytoplasm or the nucleus of the cell. Signals diffuse across the cell membrane and bind to the receptor sites on intracellular receptors, of the same cell.
- Membrane-bound receptors: These receptors extend across the cell membrane, with their receptor sites on the outer surface of the cell membrane. They respond to intercellular chemical signals that are large, water-soluble molecules that do not diffuse across the cell membrane.
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Q #9: Which of the following is a component of a chromosome?
A. Centromere
B. Gamete
C. Homologue
D. Ribose
Answer Explanation
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.
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Q #10: When would a cell most likely contain the most nucleotides?
A. S
B. G1
C. M
D. G2
Answer Explanation
A cell copies its DNA during the S phase, and nucleotides are the building blocks of DNA. Thus, the step preceding the S phase, the G1 phase, is the phase of the cell cycle when the cell would contain the most nucleotides.
For a cell to divide into more cells, it must grow, copy its DNA, and produce new daughter cells. The cell cycle regulates cellular division. This process can either prevent a cell from dividing or trigger it to start dividing.
The cell cycle is an organized process divided into two phases: interphase and the M (mitotic) phase. During interphase, the cell grows and copies its DNA. After the cell reaches the M phase, division of the two new cells can occur. The G1, S, and G2 phases make up interphase.
- G1: The first gap phase, during which the cell prepares to copy its DNA
- S: The synthesis phase, during which DNA is copied
- G2 : The second gap phase, during which the cell prepares for cell division
It may appear that little is happening in the cell during the gap phases. Most of the activity occurs at the level of enzymes and macromolecules. The cell produces things like nucleotides for synthesizing new DNA strands, enzymes for copying the DNA, and tubulin proteins for building the mitotic spindle. During the S phase, the DNA in the cell doubles, but few other signs are obvious under the microscope. All the dramatic events that can be seen under a microscope occur during the M phase: the chromosomes move, and the cell splits into two new cells with identical nuclei.
