7th Grade Science Questions On Genetics!

A Punnett square is a chart that shows all the possible combinations of alleles that can result from a genetic cross. It is commonly used in genetics to predict the probability of certain traits being inherited by offspring. It is a useful tool in understanding and visualizing the principles of Mendelian genetics, as it allows for the determination of genotypes and phenotypes in offspring.

Mutations refer to changes in a gene or chromosome that can lead to alterations in the phenotype. These changes can occur during the replication of DNA in meiosis or mitosis. Mutations can be caused by various factors such as exposure to radiation, chemicals, or errors during DNA replication. These alterations in the genetic material can result in different traits or characteristics in an organism, which is known as the phenotype.

Mitosis is the correct answer because it is the stage of the cell cycle where the cell's nucleus divides into two new nuclei. During mitosis, one copy of the DNA is distributed into each daughter cell. This process ensures that each daughter cell receives an identical set of chromosomes and genetic material.

A dominant allele is an allele whose trait always shows up in the organism when the allele is present. This means that even if there is only one copy of the dominant allele, it will be enough to express the trait. In contrast, a recessive allele requires two copies in order to be expressed. Dominant alleles have a stronger influence on the phenotype of an organism compared to recessive alleles.

A recessive allele is an allele that is masked or not expressed when a dominant allele is present. This means that the trait associated with the recessive allele will only be observed if an individual has two copies of the recessive allele, one from each parent. In the presence of a dominant allele, the trait controlled by the recessive allele will not be visible. This concept is important in understanding inheritance patterns and is often observed in selective breeding, where breeders choose specific traits by selectively breeding individuals with desired dominant alleles.

Probability refers to the likelihood or chance of a particular event occurring. It is a measure of how likely it is for an event to happen, based on the available information or previous occurrences. In the context of the given terms, probability is the most suitable explanation as it relates to the concept of determining the likelihood of an event or outcome happening. Pure breed, selective breeding, and codominance are not directly related to the concept of likelihood or probability.

Heredity refers to the passing of traits from parents to offspring. This process involves the transfer of genetic information from one generation to the next. It is responsible for the transmission of physical characteristics, such as eye color or height, as well as certain diseases or disorders. Heredity is influenced by various factors, including genes, environment, and chance. Through heredity, individuals inherit a combination of traits from their parents, which contribute to their unique genetic makeup.

Selective breeding is the process of intentionally choosing certain organisms with desired traits to be the parents of the next generation. This is done in order to enhance or maintain specific characteristics in the offspring. By carefully selecting individuals with traits that are favorable, such as high yield or disease resistance, breeders can create populations of organisms with those desired traits. This process is commonly used in agriculture and animal breeding to improve the quality and productivity of crops and livestock.

Genetics is the correct answer because it refers to the scientific study of heredity, which involves the study of genes and how traits are passed down from one generation to another. It encompasses the understanding of DNA, genetic variation, inheritance patterns, and the role of genes in determining an organism's traits and characteristics.

A gene is a segment of DNA on a chromosome that codes for a specific trait. Genes are responsible for determining the characteristics and traits of an organism. They contain the instructions for producing proteins, which are essential for the functioning and development of cells and organisms. Genes can exist in different forms called alleles, which can result in variations of a trait. Chromosomes are structures that contain genes, and traits are the observable characteristics of an organism.

A pure breed is an organism that always produces offspring with the same form of a trait as the parent. This means that the offspring will have the same characteristics and traits as the parent, without any variation. This is achieved through selective breeding, where individuals with desired traits are bred together to maintain and perpetuate those traits in future generations. Pure breeding is commonly used in agriculture and animal husbandry to develop and maintain specific breeds with desired traits.

Having two identical alleles for a trait is referred to as homozygous. Homozygous individuals have two copies of the same allele, either dominant or recessive, for a particular trait. This means that both alleles in the pair are identical, resulting in the expression of that specific trait. In contrast, heterozygous individuals have two different alleles for the trait, while codominance refers to a situation where both alleles are expressed equally in the phenotype. Mitosis, on the other hand, is a cellular process that results in the division of a cell into two identical daughter cells.

Phenotype refers to an organism's physical appearance or visible traits. It is the result of the interaction between an organism's genetic makeup (heredity) and the environment. Phenotype can be influenced by mutations, which are changes in the DNA sequence that can alter the expression of genes and lead to different physical characteristics. Therefore, phenotype is a comprehensive term that encompasses the observable characteristics of an organism.

The term "genotype" refers to an organism's genetic makeup or allele combinations. It is a combination of alleles inherited from both parents that determines the specific traits and characteristics of an organism. The genotype can include both dominant and recessive alleles, which may exhibit different levels of expression or dominance. This term is commonly used in genetics to describe the genetic composition of an individual or a population.

Mitosis is the correct answer because it is the stage of the cell cycle where the nucleus divides into two new nuclei and one copy of the DNA is distributed into each daughter cell. During mitosis, the cell undergoes a series of steps, including prophase, metaphase, anaphase, and telophase, which result in the division of the nucleus and the formation of two identical daughter cells. This process is important for growth, repair, and asexual reproduction in organisms.

A chromosome is a rod-shaped cellular structure made of condensed chromatin. It contains DNA, which carries the genetic information that controls inherited characteristics such as eye color and blood type. Chromosomes are found in the nucleus of cells and are responsible for the transmission of genetic material from one generation to the next. They play a crucial role in determining an individual's traits or characteristics, making them the correct answer in this context.

Allele refers to the different forms of a gene. Genes are segments of DNA that determine specific traits in organisms. Each gene can exist in multiple forms, known as alleles. These alleles can differ in their DNA sequence, resulting in variations in the trait that they control. For example, the gene for eye color can have alleles for blue, brown, or green eyes. Therefore, allele is the correct answer in this context.

Heterozygous refers to the condition when an individual has two different alleles for a particular trait. In this case, the individual inherits one allele from each parent, resulting in a mixed genotype. This can lead to the expression of different phenotypes, as each allele may have a different effect on the trait. In contrast, homozygous refers to the condition when an individual has two identical alleles for a trait, which can result in a more consistent phenotype. Therefore, the correct answer for the given question is heterozygous.

Meiosis is the correct answer because it is the process that occurs in sex cells (gametes) where the number of chromosomes is reduced by half. During meiosis, a single cell divides twice to produce four daughter cells, each with half the number of chromosomes as the parent cell. This reduction in chromosome number is important for sexual reproduction, as it ensures that when gametes fuse during fertilization, the resulting offspring will have the correct number of chromosomes.

A hybrid refers to an organism that has two different alleles for a particular trait. This means that the organism inherits two different versions of a gene from its parents, resulting in a combination of traits. In contrast, homozygous organisms have two identical alleles for a trait, while heterozygous organisms have two different alleles which can also be called a hybrid. Therefore, the correct answer is hybrid.

Codominance is the correct answer because it refers to a condition in which neither of two alleles of a gene is dominant or recessive. In codominance, both alleles are expressed equally and simultaneously in the phenotype of a heterozygous individual. This means that neither allele masks or dominates the other, resulting in a unique phenotype that shows traits from both alleles. This is different from incomplete dominance, where the heterozygous phenotype is an intermediate blend of the two alleles.

A trait is a characteristic that an organism can pass onto its offspring through its genes. Traits can include physical features, such as eye color or height, as well as behavioral or physiological characteristics. These traits are determined by specific genes that are inherited from the organism's parents.