Bio-Pac 05: Vocabulary Flashcards
Diploid
A cell with two of each kind of chromosomes. A cell is said to contain a diploid, or 2n, number of chromosomes .
Haploid
A cell with one of each kind of chromosomes. A cell is said to contain a haploid, or n, number of chromosomes .
Homologous Chromosomes
The two chromosomes of each pair in a diploid cell help determine what the individual organism looks like. These paired chromosomes are called homologous chromosomes .
Meiosis
The kind of cell division which produces gametes (cell involved in sexual reproduction) containing half the number as a parent’s body is meiosis .
Sperm
Male gametes (cell involved in sexual reproduction) are called sperm cells .
Eggs
Female gametes (cell involved in sexual reproduction) are called egg cells .
Zygote
When a sperm fertilizes an egg, the resulting cell, called a zygote, once again has the diploid number of chromosomes .
Sexual Reproduction
The pattern of reproduction that involves the production and subsequent fusion of haploid sex cells .
Tetrad
Each pair of homologous chromosomes come together to form a four-part structure. A tetrad consists of two homologous chromosomes, each made up of two sister chromatids .
Crossing Over
The chromatids in a tetrad pair so tightly, that non-sister chromatids from homologous chromosomes sometimes actually exchange genetic material in this process. Crossing over results in new combinations of alleles on a chromosome.
Genetic Recombination
The reassortment of chromosomes and genetic information by crossing over or by independent segregation of homologous chromosomes is called genetic recombination .
Nitrogen Base
Organic ring structure that contains one or more atoms of nitrogen. In DNA there is Adenine, Thymine, Cytosine, and Guanine.
Nucleotide
In nucleic acids, nucleotides do not exist as individual molecules. In DNA, nucleotides combine to form two long chains, producing one large molecule. Each chain of nucleotides contains single nucleotides connected to each other. The two chains of nucleotides in DNA are joined by hydrogen bonds between the bases.
Double Helix
The two chains of nucleotides in DNA are joined by hydrogen bonds between the bases, resulting in a structure that is like a ladder. When something is twisted like a coiled spring, the shape is a helix. Because DNA is composed of two twisted strands, its shape is a double helix.
Codon
Each set of three nitrogen bases representing an amino acid.
mRNA
Messenger RNA is the RNA copy that carries the information from DNA out into the cytoplasm of the cell.
rRNA
Ribosomal RNA is the portion of the DNA code for the RNA (which is copied from DNA) that makes up ribosomes. rRNA helps produce enzymes needed to bond amino acids together during protein synthesis.
tRNA
Transfer RNA brings the amino acids to the ribosomes so they can be assembled into proteins. After it brings the amino acids it goes and gets more for another process, it is not just used for one process and does not have to have a new one created for each process like mRNA and rRNA.
Stop Codon
A codon of the mRNA strand. When this is reached during protein synthesis, the protein is spit out of the ribosome and protein synthesis is done.