2.1 Cell Division Review Flashcards
What is Genetics?
It is the study of how genes pass from one generation to the next.
What is Cell Theory? (3)
- Cells are the smallest unit of life
- All living things are made of 1+ cells
- All cells are made from other cells
What are the main reasons for Cell Division? (3)
- Growth
- Replace old cells
- Repair
What happens when the cell gets too big?
- Difficulty doing normal cell functions (taking in nutrients/removing waste)
- Cytoplasm can’t exchange nor transport gases, nutrients
- Cell divides
Why do some types of cells constantly replace? Example?
Because they are in high motion areas.
Ex: skin, gut lining
Do some cells lose ability to divide at an early age? Example?
Yes
Ex: muscle cells, nerve cells
What are the Stages of the Cell Cycle? (3)
- Interphase
- Mitosis
- Cytokinesis
What happens in Interphase?
- Normal cell activities
- Growth of cell
- DNA is copied
What happens in Mitosis?
- Cell undergoes the process of nuclear division
What happens in Cytokinesis?
When?
- Cytoplasm splits equally into 2 new identical cells. (The cell membrane pinches along the equator of the cell)
- Near the END of mitosis
What are the phases of Interphase? (3)
- G1 (growth 1) Phase:
Major Growth, production of required molecules - S (synthesis) Phase:
DNA is copied - G2 (growth 2) Phase:
more growth, production of molecules for cell division
What are Somatic cells?
All cells of the body except reproductive ones.
How many chromosomes do somatic cells in humans have?
46 chromosomes
How many chromosomes do reproductive cells have?
23 chromosomes
Simply describe what happens in Mitosis (2)
- Replicated genetic material(DNA) separates
- Parent cell prepares to split into 2 daughter cells
What is Chromatid?
Chromatid: When genetic material duplicates, it creates 2 identical sister Chromatin. If they are held together to create a chromosome, each arm is chromatid.
What is Chromatin?
The strand of DNA itself, that creates the chromosome
What is a Chromosome?
It is tightly wrapped DNA
What occurs in Prophase? (4)
- Nuclear membrane + nucleolus disappears
- Cell’s chromatin condenses into chromosomes
- The Chromosome “arms” (chromatid) are held tog by a centromere
- CENTROSOMES project spindle fibers and MOVE TO OPPOSITE POLES.
What is a centrosome?
The organelle that creates spindle fibres and separates the sister chromatids/splits the chromosome.
What is a centromere?
It is what holds 2 sister chromatids together.
What happens in Metaphase?
- Spindle fibers guide the chromosomes to the equator(central line) of the cell.
- They then attach to the centromere of each chromosome.
What happens in Anaphase? (3)
- Each centromere splits apart and separates the sister chromatids
- Spindle fibres pull chromosomes to opposite poles of the cell
- Each sister chromatid is now its own chromosome
What occurs in telophase?
- Chromosomes reach the OPPOSITE POLES of the cell
- Chromosomes UNWIND into chromatin
- Spindle fibers BREAK DOWN
- Nuclear membrane starts to REFORM around the new chromosomes
What is a double helix?
Composition?
It is the two long spiral strands that make up the ‘backbone’ of DNA.
- made of: a phosphate, a sugar
What are Nucleotides?
Composition? (3)
- They are the units that create DNA strands
- Made of:
- a phosphate
- a sugar
- a base
What are the bases of DNA?
(4)
- Adenine (A)
- Thymine (T)
- Cytosine (C)
- Guanine (G)
What bases in DNA always pair together? Why?
- Cytosine (C) & Guanine (G)
- Adenine (A) & Thymine (T)
The bases are paired to hold the double helix strands together.
What do you call the pair of bases in DNA?
Complementary loose pair
What results in Genetic Mutations?
When DNA is replicated and there is a change in the sequence of bases
What differentiates one’s DNA?
The order in which the nucleotides are placed. The pattern of the nucleotides.
What does ‘Semi Conservative’ represent in DNA replication?
Why it is called that?
- When DNA replicates, the double helix splits and each separate strand is used as a template to create the 2 new strands of DNA
- ‘Semi conservative’ bc half original DNA is conserved
