What is the correct order of the stages of the cell cycle?
A. G1,S,G2,M
B. G2,S,G1,M
C. M,S,G2,G1
D. S,M,G1,G1
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.
Therefore, the Correct Answer is A.
More Questions on TEAS 7 Science
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Q #1: In the following single-replacement reaction, ______ replaces ______. Cl2+2NaI→2NaCl+I2
A. sodium, iodine
B. chlorine, iodine
C. chlorine, sodium
D. sodium, chlorine
Answer Explanation
In this reaction, chlorine (Cl2) is an element in the reaction that replaces iodine in the compound sodium iodide (NaI). This allows chlorine to form a compound with sodium (NaCl) and leaves iodine (I2) as an element.
Synthesis reactions involve two or more reactants (A and B) combining to form one product (AB). In the example provided, hydrogen (H2) and oxygen (O2) begin as separate elements. At the end of the reaction, the hydrogen and oxygen atoms are bonded in a molecule of water (H2O).
Decomposition reactions have only one reactant (AB) that breaks apart into two or more products (A and B). In the example above, hydrogen peroxide (H2O2) breaks apart into two smaller molecules: water (H2O) and oxygen (O2).
Single-replacement reactions involve two reactants, one compound (AB) and one element (C). In this type of reaction, one element replaces another to form a new compound (AC), leaving one element by itself (B). In the example, zinc replaces hydrogen in hydrochloric acid (HCl). As a result, zinc forms a compound with chlorine, zinc chloride (ZnCl2), and hydrogen (H2) is left by itself.
Double-replacement reactions involve two reactants, both of which are compounds made of two components (AB and CD). In the example, silver nitrate, composed of silver (Ag1+) and nitrate (NO31-) ions, reacts with sodium chloride, composed of sodium (Na1+) and chloride (Cl1-) ions. The nitrate and chloride ions switch places to produce two compounds that are different from those in the reactants.
Combustion reactions occur when fuels burn, and they involve specific reactants and products, as seen in the examples below. Some form of fuel that contains carbon and hydrogen is required. Examples of such fuels are methane, propane in a gas grill, butane in a lighter, and octane in gasoline. Notice that these fuels all react with oxygen, which is necessary for anything to burn. In all combustion reactions, carbon dioxide, water, and energy are produced. When something burns, energy is released, which can be felt as heat and seen as light.
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Q #2: 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 #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: Which part of the digestive system comes before the stomach?
A. mouth
B. esophagus
C. ileum
D. colon
Answer Explanation
Oral Cavity is the first part of the digestive system. It is bounded by the lips and cheeks and contains the teeth and tongue. Its primary function is to masticate, or chew, and moisten the food.
Pharynx, or throat, connects the mouth to the esophagus.
Esophagus is a muscular tube about 25 centimeters long. Food travels down it to the cardiac sphincter of the stomach.
Pyloric sphincter. The exit of the stomach.
Small intestine is about 6 meters long and consists of three parts: duodenum, jejunum, and ileum.
Large intestine, consists of the cecum, colon, rectum, and anal canal. The cecum is located where the small and large intestine meet. The primary function of the large intestine is to compress the waste and collect any excess water that can be recycled.
Colon is about 1.5 to 1.8 meters long and consists of four parts: the ascending, transverse, descending, and sigmoid colon.
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Q #5: Which is classified as a type of acid-base reaction that produces a salt?
A. Combination
B. Decomposition
C. Hydrolysis
D. Neutralization
Answer Explanation
A neutralization reaction is a type of acid-base reaction where an acid and base react to form a salt and water.
In an aqueous solution, a base increases the hydroxide concentration (OH–), while an acid increases the hydrogen ion (H+) concentration. Sometimes, neutralization reactions also occur. This type of reaction happens when an acid and a base react with each other to form water and salt. Salt is typically defined as an ionic compound that includes any cation except H+ and any anion except OH–. Consider the following example of a neutralization reaction between hydrobromic acid (HBr) and potassium hydroxide (KOH).
HBr+KOH→KBr+H2O
Not all neutralization reactions proceed in the manner where all reactants are in the aqueous phase. In some chemical reactions, one reactant may be a solid. The neutralization reaction can still proceed to completion.
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Q #6: Which statement best represents Mendel’s experiments with garden peas?
A. As a result, Mendel developed several theories that have since been disproved.
B. Mendel realized he was on an incorrect track, which led him to other experimental media
C. As a result, Mendel developed foundational conclusions that are still valued and followed today.
D. Mendel collaborated with others interested in genetics to develop heredity guidelines we still use today
Answer Explanation
Mendel developed theories of genetics that scientists around the world use today.
From experiments with garden peas, Mendel developed a simple set of rules that accurately predicted patterns of heredity. He discovered that plants either self-pollinate or cross-pollinate, when the pollen from one plant fertilizes the pistil of another plant. He also discovered that traits are either dominant or recessive. Dominant traits are expressed, and recessive traits are hidden.
Mendel’s Theory of Heredity
To explain his results, Mendel proposed a theory that has become the foundation of the science of genetics. The theory has five elements:
- Parents do not transmit traits directly to their offspring. Rather, they pass on units of information called genes.
- For each trait, an individual has two factors: one from each parent. If the two factors have the same information, the individual is homozygous for that trait. If the two factors are different, the individual is heterozygous for that trait. Each copy of a factor, or gene, is called an allele.
- The alleles determine the physical appearance, or phenotype. The set of alleles an individual has is its genotype.
- An individual receives one allele from each parent.
- The presence of an allele does not guarantee that the trait will be expressed.
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Q #7: What body system is the skeletal system most closely associated with when hematopoiesis happens?
A. Urinary system
B. Digestive system
C. Muscular system
D. Cardiovascular system
Answer Explanation
The cardiovascular system is closely associated with hematopoiesis because it includes the heart and blood vessels, which are responsible for circulating blood throughout the body. Hematopoiesis, the process of blood cell formation, primarily occurs in the bone marrow, which is part of the skeletal system. However, the cardiovascular system plays a crucial role in transporting these blood cells to various parts of the body once they are produced in the bone marrow.
So, while the skeletal system provides the site for hematopoiesis, the cardiovascular system is responsible for distributing the blood cells, making it the most closely associated system in this context.
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Q #8: If a person smells something sweet, what form of information is this initially perceived as in the nervous system?
A. Cognitive
B. Integrative
C. Motor
D. Sensory
Answer Explanation
A sensory nerve is a nerve that carries sensory signals from the external environment to the brain to the central nervous system. It is also an afferent nerve, long dendrites of sensory neurons, which sends sensory information towards the central nervous system (CNS). This information is what is sensed, using the five senses from external environment, sight, sound, smell, taste, and touch.
Motor nerves have only efferent fibers, long axons of motor neurons, that carry impulses away from the CNS to the effectors, which are typically tissues and muscles of the body.
Interneurons are nerve cells that act as a bridge between motor and sensory neurons in the CNS. These neurons help form neural circuits, which helps neurons communicate with each other.
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Q #9: What organelle is only associated with plant cells?
A. Cell wall
B. Ribosome
C. Cytoplasm
D. Golgi apparatus
Answer Explanation
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.
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Q #10: Which sequence describes the hierarchy level of biological organization?
A. Kingdom, phylum, class, order, family, genus, and species
B. Genus, class, kingdom, species, order, phylum, and family
C. Genus, class, kingdom, species, order, phylum, and family
D. Species, kingdom, genus, class, family, phylum, and order
Answer Explanation
Taxonomy is the process of classifying, describing, and naming organisms. There are seven levels in the Linnaean taxonomic system, starting with the broadest level, kingdom, and ending with the species level. For example, in the image the genus level contains two types of bears, but the species level shows one type. Additionally, organisms in each level are found in the level above it. For example, organisms in the order level are part of the class level. This classification system is based on physical similarities across living things. It does not account for molecular or genetic similarities.
