Chapter 16 Flashcards
Cell cycle
A continuous sequence of cell growth + division; the life cycle of a cell
Somatic cell
Any of the cells of a multi cellular organism except those that form gametes
Parent cell
Original cell that divides to produce two new daughter cells during cell division
Daughter cell
Any one of two cells produced from the division of a parent cell
Chromatid
Single stranded chromosome. Coiled strand of DNA formed during cell replication. Made from a piece of chromatin.
DNA
Deoxyribonucleic acid. A molecule of nucleic acid that governs processes of heredity in the cells of organisms. Found in chromosomes. Contains genetic material
Chromosome
A length of DNA and it’s associated proteins
Histones
Protein found in chromosomes: acts as scaffold around which DNA winds, enabling it to fit within the small space of the nucleus.
Chromatin
Long fibres that form chromosomes + contain DNA, a small amount of RNA, + various proteins, non- condensed form of genetic material that predominates for most of the cell cycle
Centromere
The point at which two sister chromatids of a chromosome are joined + to which the spindle fibres are attached during mitosis
Homologous Chromosome
Chromosomes that contain the same sequence as another, but that may not be made up of the same alleles: human somatic cells have 22 pairs of those known as autosomes, and females also have a homologous pair of x sec chromosomes; males have a y+ a x sex chromosome which are not homologous. Homologous chromosomes have similar bonding, centromere location and length
Autosomes
Chromosomes other than a sex chromosome human somatic cells have 22 pairs of these. Each single chromosome matches it’s pair. They are homologous pairs.
Sex chromosomes
xx or xy chromosome that carries the genes involved in determining the genetic sex if an individual. May or may not be homologous pair.
Genes
The basic unit of heredity; a specific sequence of DNA that encodes a protein, tRNA, rRNA molecule or regulates the transcription of such sequence; governs the expression of a particular trait + can be passed to offspring
Locus
Specific location on a chromosome
Alleles
Different form of the same gene occurring on homologous chromosomes
Diploid
Describing a cell that contains two pairs of every chromosome. Designated as 2n eg somatic cells
Haploid
Describing a cell containing half the number of chromosomes (n) that the diploid (2n) parent cell contains; condition occurring in gametes, either egg (ovum) or sperm
Gametes
Male or female haploid reproductive cell eg: egg (ovum) + sperm
Polyploid
Describing a cell which contains sets of more than 2 homologous chromosomes
Karyotype
The particular set of chromosomes that an individual posses
Interphase
Growth stage of a somatic cell; there are 3 phases G1, S + G2; ends when the cell begins the process of nuclear division (mitosis)
G1 phase
The first part of interphase, a somatic cells growth stage during which cells carry out rapid growth + metabolic activity
Also known as Growth 1 of Gayo 1
S Phase
The middle part of interphase, a somatic cells growth stage, during which the cells DNA is replicated to create two identical chromosomes (sister chromatids)
Sister Chromatids
Two chromatids in a chromosome that are genetically identical + are held together by a centromere. Formed when a chromatid replicates itself
G2 Phase
The last part of interphase, a somatic cells growth stage, during which cells rebuild it’s reserves of energy + manufacturers proteins + other molecules to prepare for division
Also known as Growth 2 or Gap 2
Mitosis
One of the two main processes in cell division: division of the genetic material + the contents of the cells nucleus into two complete + separate sets; results in a daughter cell receiving the exact number of chromosomes + genetic make up as the parent cells
Cytokineses
One of the two main processes in cell division; consists of separation of cytoplasm and organelles and the formation of two daughter cells
Prophase
First of the 4 phases in cell division (mitosis) when chromatin condenses + can be seen tightly packed chromosomes; the nuclear membrane breaks down, centrioles move to opposite poles of the cell + the spindle apparatus forms
Centrioles
One pair of cylindrical organelles that moves to opposite poles of the cell during prophase of mitosis provides an attachment for the spindle apparatus
Spindle fibres
Made of microtubules (hollow tubes of protein that facilitate movement of chromosomes within a cell. A spindle fibre lengthens with the addition of microtubule sub units. The removal of these sub units shortens the spindle fibre
Spindle Apparatus
Assembly that carries out the separation of chromosomes during cell division (mitosis); composed of spindle fibres + assembled during prophase
Metaphase
The 2nd stage of cell division (mitosis) during which chromosomes line up at the cells equator in preparation for separation.
Anaphase
A late stage of cell division (mitosis) during which the centromere splits apart chromosomes move to opposite poles of the cell; by the end of phase; one complete diploid set of chromosomes gathered at each pole
Telophase
The final stage of cell division (mitosis) in which a nucleolus forms around chromosomes at opposite ends of the dividing parent cell; this stage is followed by cytokinesis to form two daughter cells
Cell plate
Structure across a dividing plant cell that signals the location of a new plasma membrane + cell walls
Cancer
Group of diseases associated with uncontrolled rapid cell division
Meiosis
The cellular process that produces haploid gametes from diploid cells in the ovaries + testes
Reduction Division
One of the outcomes of meiosis; cell division that produces daughter cells with fewer chromosomes than the parent cells
Recombination
One of the outcomes of meiosis; cell division that produces daughter cells with different combinations of genes than the parent cells; gives rise to offspring that are genetically distinct from one another + from their parents
Meiosis 1
The 1st of two sequences in meiotic cell division in which the chromosomes are reduced from diploid to haploid
Meiosis II
The 2nd of two sequences in meiotic cell division in which each of the haploid cells created during meiosis I undergoes mitosis with an interphase
Germ cell
Gamete- producing cell in the male + female gonads
Synapse
Junction between two neurons or between a neuron + an effector (muscle or gland)
Tetrad
A homologous pair formed during prophase I of meiosis, so named because it contains four chromatids
Non-Sister Chromatids
dna tetrad, those chromatids that do not belong to the same chromosome; undergo crossing over during prophase I of meiosis
Crossing over
The process by which non-sister chromatids exchange genes during prophase I of meiosis allowing for the recombination of genes
Non disjunction
Failure of homologous chromosomes pairs or sister chromatids to separate during meiosis I + meiosis II, respectively
Spermatogenesis
The process of male gamete (sperm) production in animals
Oogenesis
The process of female gamete (ova or egg) production in animals
Spermatogonium
The diploid germ cell from which sperm are produced in the testes
Primary Spermatocyte
One of two daughter cells formed by division of the spermatogonia: the other daughter cell replenishes the spermatogonia population
Secondary Spermatocyte
Each of the two cells produced as a result of a primary spermatocyte undergoing meiosis I