chapter 3 Flashcards
(25 cards)
The basic structural and functional unit of living organisms. All organisms are made up of one or more cells.
Cell
All living things are made of one or more cells.
The cell is the basic unit of structure and function in living things.
All cells come from pre-existing cells.
Cell theory
Cells without a nucleus or membrane-bound organelles. Prokaryotes are simpler and smaller than eukaryotic cells.
Prokaryotic Cell
cells with a nucleus and membrane-bound organelles. More complex than prokaryotic cells.
Eukaryotic Cell
A thread-like structure made up of DNA and proteins. Found in the nucleus of eukaryotic cells and in the cytoplasm of prokaryotic cells.
Chromosome
A unit of heredity that is transferred from a parent to offspring. It determines some characteristic of the offspring.
Gene
A molecule that carries genetic instructions for growth, development, and reproduction.
DNA (Deoxyribonucleic Acid)
A type of cell division that reduces the chromosome number by half, producing four genetically different cells (gametes or spores).
Meiosis
A type of cell division that results in two daughter cells, each identical to the parent cell. Used for growth and repair.
Mitosis
A cell that contains one set of chromosomes (n). Found in gametes (sperm and egg cells).
Haploid
A cell that contains two sets of chromosomes (2n). Found in somatic (body) cells.
Diploid
Pairs of chromosomes, one from each parent, that have the same structure and gene sequence.
Homologous Chromosomes
The exchange of genetic material between homologous chromosomes during meiosis. It increases genetic variation.
Crossing Over
A version of a gene that determines a specific trait.
Allele
An allele that expresses its trait even when only one copy is present.
Dominant Allele
The genetic makeup of an organism.
Genotype
An allele that only expresses its trait when two copies are present.
Recessive Allele
The physical traits or characteristics of an organism determined by its genotype.
Phenotype
An organism with two identical alleles for a trait (e.g., AA or aa).
Homozygous
An organism with two different alleles for a trait (e.g., Aa).
Heterozygous
Any chromosome that is not a sex chromosome.
Autosome
A chromosome involved in determining the sex of an organism (e.g., X and Y chromosomes).
Sex Chromosome
A change in the DNA sequence that may result in a different trait.
Mutation
A haploid cell involved in sexual reproduction (sperm or egg).
Gamete
