Chapter 12: Textbook Flashcards
Genome
Genetic information of the cell
What do chromosomes consist of?
One very long linear DNA molecule associated with many proteins
Building material of chromosomes
Chromatin
In both prokaryotes and eukaryotes, most cell division involves the distribution of
Identical genetic material to 2 daughter cells
What is meiosis
Special type of eukaryotic cell division that can produce sperm and eggs
What are gametes
Reproductive cells
What does each duplicated chromosome consist of?
2 sister chromatids
What are sister chromatids
Joined copies of the original chromosome
Define cohesion
When sister chromatids containing identical DNA molecule are attached all along their lengths by protein complexes which is known as sister chromatid cohesion
Centromere
Region of repetitive sequences in the chromosomal DNA where the chromatid is attached most closely
What do molecular and mechanical processes do to sister chromatids
Separate them into 2 chromosomes and distribute them to 2 daughter cells
Define mitotic spindle
Fibres made of microtubules which begin to form during prophase - mitosis depends on this process
What happens in the G2 phase of interphase
A nuclear envelope encloses the nucleus
Chromosomes are not yet condensed
2 centrosomes have formed
Cytokinesis in animal vs plant
Animal: cleavage furrow
Plant: cell plate
Define centrosome
Sub cellular region containing material that functions throughout the cell cycle to organize the cell’s microtubules
Define kinetochore
A structure made up of proteins that have assembled on specific sections of DNA at the centromere
Metaphase plate
Chromosomes line up at the equator which is called the metaphase plate
Enzyme that cleaves the cohesions holding chromatids together
Separase
What is on the cytoplasmic side of the furrows in animal cells
Contractile ring of actin and micro filaments
Define binary fission
Meaning “division in half” - cells grow to roughly double its size and then divides to form 2 cells in bacteria
Define cell division in bacteria
Origin of replications move rapidly towards the opposite ends of the cell allowing the bacteria to reach twice its size and then the plasma membrane pinches inward to divide the parent into 2 daughter cells
Explain cell division in dinoflagellates
Chromosomes attach to the nuclear envelope and microtubules pass through the nucleus inside cytoplasmic tunnels
Explain cell division in diatoms and some yeast
Microtubules form a spindle within the nucleus and separate the chromosomes and the nucleus splits into two daughter nuclei
In most eukaryotes where does the spindle form
Outside the nucleus and the envelope breaks down during mitosis allowing microtubules to separate the chromosomes and 2 nuclear envelopes are then formed
Define the cell cycle control system
A cyclically operating set of molecules in the cell that both triggers and coordinates key events in the cell cycle
Define cyclin
A protein that gets its name from its cyclically fluctuating concentration in the cell
Kinase must be attached to a
Cyclin since they’re called cyclin dependent kinases
When is the synthesis of cyclin
In the late S phase and continues through G2 since it’s protected from degradation
How does MPF promote mitosis
By phosphorylating various proteins
Why are checkpoints important?
Dubbed the restriction point since they check and report whether all the cellular processes were done right and whether or not the cell cycle should proceed
Define growth factor
Protein released by certain cells to stimulate other cells to divide
What is density dependent inhibition
A phenomenon in which crowded cells stop dividing
Cells that acquire the ability to divide indefinitely are called
Transformation
Tumor cells can
Separate from the original tumour, enter blood vessels and travel to other parts of the body to create a new Tumor
Metastasis
Spread of cancer cells to locations distant from their original site
