Genes
What is the importance of genes?
- contain instructions that determine looks
What is a chromosome?
location of information for genes
what is meiosis?
the process in eukaryotic, sexually-reproducing organisms that reduces the number of chromosomes in gametes
What is mitosis?
Where a cell divides into 2 daughter cells (cell division)
what is the cell cycle?
A series of events that takes place in a cell as it grows and divides
When are dominant traits expressed?
Always expressed when the allele connected is dominant
What are homologous chromosomes?
chromosomes that have the same genes and different alleles
What is the goal of meiosis 1 and meiosis 2?
1. separate DNA into 2 daughter cells
2. separate 2 alleles of each gene into cells
What are the 5 stages of mitosis?
1. prophase
2. prometaphase
3. metaphase
4. anaphase
5. telophase
what type of cell does mitosis produce?
somatic cells
Who was Francis Crick?
Proposed the genetic code hypothesis stating that the sequence of bases DNA acted as a code.
What are deleterious mutations?
decrease fitness of organism, harmful, negative affect
What is crossing over and what stage does it happen in?
an important step between prophase 1 and metaphase 1 where homologous chromosomes can swap parts of themselves that house the same gene.
What happens in cytokinesis and where does it take place in the stages?
after telophase, responsible for splitting the two cytoplasm's into two separate cells
what are the basic steps in cellular replication?
1. copying the DNA
2. Separating the DNA
3. Dividing the cytoplasm to create two complete cells
When are recessive traits expressed?
only if there is no dominant alleles connected
- both connecting alleles are recessive
what are sister chromatids?
identical chromosomes
What is the Result of meiosis 1 and 2?
1. 2 new haploid cells
2. 4 haploid cells
Where does the cell spend most of its life?
interphase
mitosis (prophase, metaphase, anaphase, telophase)
What is the difference between genotype and phenotype
genotype = refers to the exact pairing of alleles (inside)
Phenotype = refers to the expression of trait (outside)
What are the 4 types of chromosomal mutations and what do they do?
1. inversion - segment of chromosome flips
2. translocation - section of chromosome breaks off and switches to another one
3. deletion - segment of chromosome is lost
4. duplication - segment of chromosome doubles
What is a zygote?
the result of two fused cells
What happens in prometaphase?
transition stage, nuclear envelope goes away
What are the four stages in the cell cycle, and what occurs during each stage?
1. Gap 1 (G1) = cell increases in size
2. Synthesis (S) = cell copies its DNA
3. Gap 2 (G2) = cell prepares to divide
4. Mitosis (M) = cell divides