Genetics unit terms Flashcards
Function of DNA
carries genetic information of the cell
Chromosome structure
a threadlike structure composed of a single dsDNA molecule wrapped around histone proteins structure
What is a centromere
attachment site for proteins/ other chromosomes
What are sister chromatids
A copied form of the same gene joined together (still count as one chromosome)
What are genes?
Short sections of DNA that codes for a functional protein or RNA molecule. Each gene occupies a specific location on a chromosome
Locus
location of specific gene
Allele
specific part of a gene that is responsible for variation in inherited traits
What causes mutations?
mistakes when DNA is replicated, and environmental factors
What is the haploid number?
the number of “kinds” of chromosomes (n)
- human haploid number is 23
What is the diploid number?
number of chromosomes (2n)
- human diploid number is 46
What is ploidy?
The number of copies of each type of chromosome
What is a homologous chromosome or homolog?
Chromosomes that have:
- the same genes (in the same position/locus); same or different alleles-same size*
- same shape*
- same centromere position*
What is a genotype?
Specific alleles of a particular set of genes being studied
What is heterozygous?
2 different alleles for the same gene
What is homozygous?
2 copies of the same alleles for the same gene
2 important concepts of cell theory
- All organisms are made of cells
2. All cells come from pre-existing cells
What four things must occur before cell division can take place?
- The cell must grow (so daughter cells are normal in size)
- Synthesize cytoplasm and organelles (so daughter cells can function)
- Copy the DNA (for each daughter cell)Nuclear division can then begin.
- The cell must also ensure that each daughter cell inherits a nucleus containing undamaged chromosomes of the appropriate ploidy.
What are the four phases of the cell cycle?
G1 —>S —>G2 —>M
When do the three checkpoints of the cell cycle occur?
- before S phase (during G1)
- before M phase (during G2)
- during M phase
What three phases occur during interphase?
G1, S, G2
Autosome
any chromosome that is not a sex chromosome, each copy has same structure.
unreplicated chromosome
a chromosome that consists of one double helical molecule of DNA packaged with proteins for compactness
replicated chromosome
Chromosome after DNA replication consists of 2 identical chromatids, each containing one double-helical DNA packaged with proteins for compactness
Sister chromatids
2 identical chromatid copies in a replicated chromosome
