LE HW4.2.9

2.

The individualtiy of an organism is determined by the

Sequence of bases in DNA
Number of amino acids in a cell
Position of ribosomes in the cytoplasm
Number of bases in the mitochondria

Correct Answer

A. Sequence of bases in DNA

Explanation

The sequence of bases in DNA determines the individuality of an organism because it contains the genetic information that codes for the production of proteins and other molecules essential for an organism's structure and function. The specific arrangement of bases in DNA determines the sequence of amino acids in proteins, which ultimately determines an organism's traits and characteristics. Therefore, any changes in the sequence of bases can lead to variations in protein structure and function, resulting in different traits and individuality among organisms.

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3.

A change in the sequence of bases in a DNA molecule is most accurately referred to as

A mutation
A chromosomal replication
Carbohydrate molecule synthesis
Selective breeding

Correct Answer

A. A mutation

Explanation

A change in the sequence of bases in a DNA molecule is most accurately referred to as a mutation because a mutation is any alteration in the DNA sequence. This can involve the addition, deletion, or substitution of nucleotides, which can lead to changes in the genetic code and potentially result in different traits or characteristics. Chromosomal replication refers to the process of copying an entire chromosome, carbohydrate molecule synthesis refers to the production of carbohydrates, and selective breeding involves the intentional breeding of organisms with desirable traits.

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4.

The sequence of amino acids that makes up a protein molecule is determined by the sequence of

Bases in DNA
Glucose in DNA
Ribosomes in the cytoplasm
Chloroplasts in the vacuoles

Correct Answer

A. Bases in DNA

Explanation

The sequence of amino acids in a protein molecule is determined by the sequence of bases in DNA. DNA contains the genetic information that is transcribed into RNA, which is then translated by ribosomes in the cytoplasm to synthesize proteins. The sequence of bases in DNA acts as a template for the synthesis of mRNA, which carries the information to the ribosomes. The ribosomes read the mRNA sequence in groups of three nucleotides called codons, and each codon codes for a specific amino acid. Therefore, the sequence of bases in DNA ultimately determines the sequence of amino acids in a protein molecule.

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5.

Mutuations can be transmitted to the next generation if they are present in

Brain cells
Egg cells
Body cells
Muscle cells

Correct Answer

A. Egg cells

Explanation

Mutations can be transmitted to the next generation if they are present in egg cells. This is because egg cells, also known as ova or oocytes, are the female reproductive cells that carry genetic information. During fertilization, when an egg cell is fertilized by a sperm cell, the resulting embryo inherits genetic material from both parents, including any mutations present in the egg cell. In contrast, mutations present in other types of cells, such as brain cells, body cells, or muscle cells, would not be passed on to the next generation as they are not involved in the formation of new individuals.

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6.

Overexposure of animals to X-rays is dangerous because X-rays are known to damage DNA. A direct result of this damage is cells with

Unusually thick cell walls
No organelles located in the cytoplasm
Abnormally large chloroplasts
Changes in chromosomal structure

Correct Answer

A. Changes in chromosomal structure

Explanation

Overexposure to X-rays can lead to damage in DNA, which can result in changes in chromosomal structure. X-rays have high energy and can cause breaks in the DNA strands, leading to rearrangements or deletions of genetic material. These changes in chromosomal structure can have significant effects on the functioning of cells and can potentially lead to genetic disorders or diseases.

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7.

In all living cells, DNA controls cellular activities by

Determining the order of amino acids in protein molecules
Regulating the concentration of molecules on both sides of the cell membrane
Varying the rates of starch synthesis
Coordinating active and passive transport

Correct Answer

A. Determining the order of amino acids in protein molecules

Explanation

DNA controls cellular activities by determining the order of amino acids in protein molecules. This is because DNA contains the genetic code that specifies the sequence of amino acids in proteins. Through the process of transcription and translation, DNA is used as a template to produce messenger RNA (mRNA), which carries the genetic information from the nucleus to the ribosomes. The ribosomes then use this mRNA to synthesize proteins, following the instructions encoded in the DNA. The order of amino acids in a protein determines its structure and function, and therefore DNA plays a crucial role in controlling cellular activities through protein synthesis.

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8.

A dog breeder can determine that the sudden appearance of hairlessness in one of the pubbies is a mutation if the dog

Is still hairless after 5 years
Shows no change in the hairless condition after its diet is changed
Develops other conspicuous differences from the parent
Is bred and the trait is capable of being inherited

Correct Answer

A. Is bred and the trait is capable of being inherited

Explanation

The correct answer is "is bred and the trait is capable of being inherited." This answer suggests that the dog breeder can determine that the sudden appearance of hairlessness in one of the puppies is a mutation if the trait can be passed on to future generations through breeding. This indicates that the hairlessness is not a temporary condition or caused by external factors such as diet, and instead, it is a heritable trait resulting from a genetic mutation.

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9.

Which mutation could be passed on to future generations?

A gene change in a liver cell
Cancer caused by excessive exposure to the sun
A chromosomal alteration during sperm formation
Random breakage of a chromosome in a leaf cell of a maple tree

Correct Answer

A. A chromosomal alteration during sperm formation

Explanation

A chromosomal alteration during sperm formation can be passed on to future generations because sperm cells carry genetic information that is passed on to offspring during reproduction. This alteration in the chromosomes can result in changes in the genetic code, leading to the inheritance of certain traits or genetic disorders by future generations.

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10.

Although identical twins inherit exact copies of the same genes, the twins may look and act differently from each other because

A mutation took place in the gametes that produced the twins
The expression of genes may be modified by environmental factors
The expression of genes may be different in males and females
A mutation took place in the zygote that produced the twins

Correct Answer

A. The expression of genes may be modified by environmental factors

Explanation

Identical twins inherit the same genes, but they may look and act differently from each other because the expression of genes can be influenced by environmental factors. These factors can include differences in nutrition, exposure to toxins, lifestyle choices, and experiences. The environment can impact how genes are turned on or off, leading to variations in physical appearance, behavior, and other traits between identical twins.

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Le Hw4.2.9

In DNA, the base represented by an A always pairs with the base represented by

Quiz Preview

The individualtiy of an organism is determined by the

A change in the sequence of bases in a DNA molecule is most accurately referred to as

The sequence of amino acids that makes up a protein molecule is determined by the sequence of

Mutuations can be transmitted to the next generation if they are present in

Overexposure of animals to X-rays is dangerous because X-rays are known to damage DNA. A direct result of this damage is cells with

In all living cells, DNA controls cellular activities by

A dog breeder can determine that the sudden appearance of hairlessness in one of the pubbies is a mutation if the dog

Which mutation could be passed on to future generations?

Although identical twins inherit exact copies of the same genes, the twins may look and act differently from each other because