Cell Reproduction Terms Part 1 Flashcards
Condensed chromatin structure formed when cells replicate.
Chromosomes
One half of a chromosome. Two sister chromatids are joined by a centromere to form a chromosome.
Chromatid
The long strands that form chromosomes and contain DNA, RNA and various proteins. Found in the nucleus of cells.
Chromatin
One of two chromosomes that are genetically identical and held together at the centromere.
Sister chromatids
One of the different forms of the same gene
Alleles
Governs expression of a trait
Gene
X or Y chromosome; determines genetic sex (Female = XX; Male = XY)
Sex chromosomes
Chromosomes with the same gene sequence
Homologous chromosomes
Cells with two pairs of homologous chromosomes. The ——— number in humans is 46, or 23 pairs.
Diploid cell
Cell with half the number of chromosomes as diploid. Human gametes, or reproductive cells (egg and sperm cells), are ———. (The ——— number of chromosomes in a species is designated as n. In humans, n = 23, and a diploid cell has 2n chromosomes (2n = 46).)
Haploid cell
An individuals complete set of chromosomes.
Karyotype
The cell grows quickly during this phase, making new cell molecules (except DNA).
G1 phase
The DNA in the chromatin replicates to create an identical copy of DNA. These two identical chromosomes, called sister chromatids are joined at the centromere.
S phase
This second growth stage lets the cell rebuild its reserves of energy to prepare for division. As well, the cell manufactures proteins and other molecules to make structures required for division of the nucleus and cell.
G2 phase
Refers to a body cell
Somatic cell
Sex cell (egg or sperm)
Germ cell
Growth phase; includes G1, S phase, and G2
Interphase
It is a continuous process that involves two stages: mitosis and cytokinesis
Division Stage
Division of the cell’s nucleus where the daughter cells receive the exact number of chromosomes and genetic makeup as the parent cell.
Mitosis
Separation of the cytoplasm and the formation of two new daughter cells; occurs after telophase of mitosis
Cytokinesis
Chromosome other than sex chromosome
Autosome
A membrane that encloses the nucleus
Nuclear membrane
Is a barrel-shaped cell structure involved in the organization of the mitotic spindle and in the completion of cytokinesis
Centrioles
One of a network of fibres that forms the spindle apparatus during cell division (mitosis); made of mictotubules, hollow tubes of protein that facilitate movement of chromosomes within a cell.
Spindle fibres
Is a region of DNA typically found near the middle of a chromosome where two identical sister chromatids come closest in contact.
Centromere
A plasma membrane invagination at the cell division site.
Cleavage furrow
A eukaryotic cell formed by a fertilization event between two gametes. (Sexual reproduction requires the fusion of a male and a female reproductive cell to produce a ——.
A —— receives half its genetic material from the female parent and the other half from a male parent.
Zygote
- a advanced cell
- a more complex cell with a true nucleus and membrane bound organelles such as E.R., ribosomes, Golgi apparatus, etc…
- ex. These are in cineplex organisms such as humans and other animals. (Ex: blood cells, liver cells, muscle cells, nerve cells)
Eukaryotic
- primitive cell
- a simple cell with NO true nucleus
- ex: simple organisms have these cells. (Bacteria, amoeba, paramecium, single cell organisms)
Prokaryotic
- primitive cell
- a simple cell with NO true nucleus
- ex: simple organisms have these cells. (Bacteria, amoeba, paramecium, single cell organisms)
Prokaryotic
The life of a cell. Can be divided into two main stages: interphase and cell division.
Cell cycle
- The chromatin condenses into tightly packed chromosomes.
- The nuclear membrane breaks down, releasing the chromosomes into he cytoplasm.
- The nucleolus disappears.
- One pair of centrioles move apart to opposite poles of the cell.
As the centrioles move apart, a network of fibres called the spindle fibres forms between them. Each spindle fibre is made of microtubules.
Prophase
- The spindle fibres guide the chromosomes to the equator, or centre line, of the cell.
- The spindle fibres from opposite poles attach to the centromere of each chromosome.
Metaphase
- Each centromere splits apart and the sister chromatids separate from one another.
- The spindle fibres that link the centromeres to the poles of the cell shorten. As there fibres shorten, sister chromatids are pulled to opposite poles.
- At the end of anaphase, one complete diploid set of chromosomes has been gathered at each pole of the elongated cell.
Anaphase
- The chromatids begins to unwind into longer and less visible strands of chromatin.
- The spindle fibres break down.
- A nuclear membrane forms around each new set of chromosomes.
- A nucleolus forms within each new nucleus.
Telophase
male or female reproductive cell
Gamete
A four-part structure that forms during prophase I of meiosis and consists of two homologous chromosomes, each composed of two identical chromatids.
It’s made up of a pair of sister chromatids synapsed with another pair of sister
chromatids. In the middle of it, two homologous but non-identical chromatids, which are called non-sister chromatids, lie side by side. This alignment of non-sister chromatids plays an important role in genetic recombination.
Tetrad
a type of cell division that reduces the number of chromosomes in the parent cell by half and produces four gamete cells. This process is required to produce egg and sperm cells for sexual reproduction.
Meiosis
- In prophase I, each pair of homologous chromosomes align side by side. This aligning of homologous chromosomes is called…
- The pairing of two chromosomes that occurs during meiosis. It allows matching-up of homologous pairs prior to their segregation, and possible chromosomal crossover between them. It takes place during prophase I of meiosis.
synapsis
- While they are lined up side by side, non-sister chromatids may exchange pieces of
chromosome in a process known as… - The exchange of genes between two chromosomes, resulting in non-identical chromatids that comprise the genetic material of gametes. This process occurs during Prophase I of Meiosis, just prior to chromosome alignment and splitting of the cell.
Crossing Over
- two homologous but non-identical chromatids
- contain the same genes but may have different alleles at the same loci. They are not exact copies of each other.
non-sister chromatids
male gamete
Sperm Cell
female gamete
Ovum (egg)
process of male gamete production
Spermatogenesis
process of female gamete production
Oogenesis
involves the production of gametes by meiosis, followed by fertilization
between genetically distinct parental gametes to produce genetically distinct offspring.
Sexual reproduction
the reproductive process in which a parent organism produces genetically identical offspring.
Asexual reproduction
a diploid germ cell (spermatogenesis)
spermatogonium
a diploid germ cell (genesis)
oogonium
