Cell Cycle
What are the 3 main phases of the cell cycle?
Interphase, mitosis, cytokinesis
What is mitosis?
Mitosis is a process of cellular division that creates two genetically identical diploid cells
What is meiosis?
Meiosis is a process of reduction division that results in 4 genetically diverse haploid cells (gametes)
What is DNA?
DNA (deoxyribonucleic acid) is the molecule that carries genetic information inside every nucleus that holds the instructions for our bodies. It controls the development & functioning of an organism
What are at least 3 similarities between meiosis & mitosis?
Both start as diploid cells, go through interphase first, DNA is replicated, produce new cells, go through the same basic steps
What happens during interphase?
The cell grows, replicated it's DNA, & goes about it's normal cell functions.
G1 - Cell grows & organelles are doubled
S - DNA is replicated
G2 - Cell prepares for mitosis & continues to grow
What are the stages of mitosis in order?
Prophase, metaphase, anaphase, telophase
Bonus points! - What is the main event that happens at each step?
What are the stages meiosis in order?
Prophase I, Metaphase I, Anaphase I, Telophase I, Prophase II, Metaphase II, Anaphase II, Telophase II
What is RNA?
RNA (ribonucleic acid) is a molecule that converts the information within DNA into a format usable to build proteins.
What are 3 major differences between mitosis & meiosis?
Mitosis: 1 division, 2 genetically identical diploid cells, purpose of growth & repair, chromosome number remains the same, happens in somatic/body cells,
Meiosis: 2 division, 4 genetically diverse haploid cells, purpose of reproduction, chromosome number is halved, happens in gametes
How does the cell prepare for cellular division during the S phase?
DNA is replicated
Bonus Points! - At the end of DNA replication for humans how many chromosomes are there? How many chromatids?
What are the 3 events that happens during prophase?
The DNA condenses into chromosomes (sister chromatids), spindle fibers begin to form, and the nuclear membrane brakes down.
What is the purpose of meiosis?
The purpose of meiosis is to create gamete cells that have genetic variety
Bonus Points! - Why would genetic variety be important in gamete cells?
What are the functions of DNA & RNA within the cell?
DNA is responsible for storing & transferring genetic information
RNA directly codes for animo acids & acts as a messenger between DNA & ribosomes to make proteins.
Why would it be false to say that meiosis is mitosis happening twice?
Meiosis & mitosis each have distinct purposes, result in different numbers of daughter cells, & involve different stages. If we were to say meiosis is mitosis twice than at the end we would have identical diploid cells not suitable for reproduction nor would they have genetic variation
What is the role of cytokinesis in the cell cycle?
Cytokinesis completes the separation of the 2 daughter cells ensuring that each daughter set has a complete set of organelles and only 1 nucleus.
What is the role of spindle fibers in mitosis?
Spindle fibers are a protein structure created during prophase that are needed to arrange & equally divide the chromosomes during metaphase, anaphase, & telophase.
What two processes help create genetic variety during meiosis?
Crossing over (recombination) & independent assortment
Bonus Points - When do these to processes happen?
How does DNA replicate?
Every time a cell divides the DNA is first replicated during the S phase of interphase. First the DNA is "unzipped" the 2 strands are separated & then other proteins will come in to match the nucleotides to create 2 new strands of DNA.
Bonus Points! - What are the matching pairs of nucleotides?
How does genetic variation occur in meiosis & mitosis?
Meiosis - Through crossing over & independent assortment
Mitosis - Through mutations
What is the purpose of the cell cycle?
To duplicate accurately the DNA in chromosomes & divide it into 2 genetically identical daughter cells with each a full set of organelles.
What is the purpose of mitosis?
The purpose of mitosis is for growth & repair?
Bonus Points! - Why is growth & repair in organisms important?
How does crossing over contribute to genetic variation in meiosis?
Crossing over is a process that occurs between homologous chromosomes during prophase I. During which part of 1 chromosome is exchanged with another creating an unique pattern of genetic material
What is DNA's role in protein synthesis?
Protein synthesis consists of transcription & translation. Transcription - DNA is used as the code to make RNA. RNA leaves the nucleus to go to a ribosome for translation. Translation - the genetic information encoded in the RNA from the DNA will be read to bring in amino acids to create a protein.DNA is unzipped & paired nucleotides are brought in & attached to create 2 new copies of DNA
What would be the conconsequences of genetic variation within meiosis & mitosis?
Meiosis - The new combinations of gene variants (alleles) makes organisms more or less able to survive & reproduce
Mitosis - A mistake in mitosis would lead to genetic variation & thus the genetic code being altered. This can lead to improper development, genetic disorders, or cancer