Genes and Heredity

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Gene Noun

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[jeen]

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Gene

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A segment of DNA on a chromosome that contains the instructions for a specific trait or protein.

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Example: This image shows the DNA double helix with labeled bases, illustrating how genes are segments of DNA that code for traits.

Front

Chromosome Noun

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[kroh-muh-sohm]

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Chromosome

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A thread-like structure in a cell's nucleus that contains DNA passed from one generation to the next.

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Example: This image shows how DNA coils into nucleosomes, forming a chromosome in the cell nucleus.

Front

Sex Cell Noun

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[seks sel]

Back

Sex Cell

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A reproductive cell, such as a sperm or egg, containing half the number of chromosomes as a body cell.

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Example: The image shows how a sperm and egg each have 23 chromosomes, combining to form a zygote with 46 chromosomes.

Front

Zygote Noun

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[zai-goht]

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Zygote

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A fertilized egg cell that forms from the fusion of a sperm and an egg during sexual reproduction.

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Example: The image shows how a sperm fertilizes an egg to form a zygote, with clear labels and arrows.

Front

DNA Noun

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[dee-en-ey]

Back

DNA

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Deoxyribonucleic acid, the molecule that carries the unique genetic instructions for an organism's development and functioning.

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Example: The image shows a DNA double helix with labeled base pairs, illustrating how genetic information is stored.

Front

Base Pair Noun

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[beys pair]

Back

Base Pair

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Two complementary nitrogenous bases that are connected by hydrogen bonds, forming the rungs of the DNA double helix.

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Example: The image shows how adenine pairs with thymine and guanine pairs with cytosine in DNA.

Front

Protein Synthesis Noun

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[proh-teen sin-thuh-sis]

Back

Protein Synthesis

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The cellular process where genetic information from a gene is used to construct a specific protein.

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Example: The image shows how mRNA, tRNA, and amino acids work together in the ribosome to synthesize proteins.

Front

Allele Noun

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[uh-leel]

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Allele

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One of the different forms or variations of a particular gene that can exist at a specific chromosomal location.

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Example: This image shows how alleles are different forms of a gene, using earlobes as an example.

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Homologous Chromosomes Noun

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[hoh-mol-uh-guhs kroh-muh-sohmz]

Back

Homologous Chromosomes

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A pair of chromosomes, one inherited from each parent, that have the same genes at the same locations.

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Example: Two pairs of chromosomes, each with sister chromatids, showing homologous chromosomes.

Front

Crossing Over Noun

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[kros-ing oh-ver]

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Crossing Over

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The exchange of genetic material between homologous chromosomes during meiosis, creating new combinations of alleles.

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Example: The image shows chromosomes exchanging genetic material during meiosis, illustrating crossing over.