Animal Cells (Part Six) Flashcards
(33 cards)
Describe the movement of
a) Flagella
b) Cilia
a) Flagella = propeller-like motion
b) Cilia = back-and-forth beating
How many beats per second in the
a) Flagella?
b) Cilia?
a) Flagella = 10-40 beats/second
b) Cilia = 12-20 beats/second
Name the core of the cilium/flagellum.
What is it made from?
Core of cilium and flagellum = The Axoneme.
It is made from microtubules.
In what stage of mitosis do centrioles participate in microtubule formation?
Interphase
How many heads in the axonemal
a) Outer-arm dyenin?
b) Inner-arm dyenin?
a) Axonemal outer-arm dyenin = 3 heads
b) Axonemal inner-arm dyenin = 1 or 2 heads
Most cells form a non-motile primary cilium.
What is its function?
- Detects signals that govern cell proliferation
- Senses flow and bending
- Essential for developmental processes
Give 6 places where non-motile cilia can be found in the human body.
- Inner ear
- Kidney
- Bile duct
- Pancreas
- Bone/cartilage
- Eye
What does a stimulus at a primary cilium result in?
Membrane depolarisation
What supports the formation and function of the cilium?
Explain.
Intraflagellar transport.
- Rafts travel along the Axoneme.
- Kinesin and dynein drive the bidirectional transport
Name the process by which actin polymerises.
Treadmilling
What are ‘stress fibres’ composed of?
F-actin and Myosin II.
What is cell motility useful for in the body?
- Protecting against pathogens
- Healing wounds
- Organ development
Give the distinct steps where M-phase occurs.
- Chromosome alignment
- Chromosome separation
- Cell division
Give the sub-phases of M-phase.
- Prophase
- Metaphase
- Anaphase
- Telophase
What happens during Prophase?
- Chromosomes condense
- Nuclear envelope disrupts
- Spindle is formed
What happens during Metaphase?
- Microtubules make contact with chromosomes
- Chromosomes are positioned in one plane
What happens during Anaphase?
- Microtubules and motors pull on chromosomes
- Chromatids move to the poles
- Rapid elongation of the spindle
- Formation of a contractile ring
What happens during Telophase?
- Cell middle contracts and separates (Cytokinesis)
- The chromosomes de-condense
- The nuclear envelope is formed
Name the structures that branch from the centrosome in the mitotic spindle.
Astral microtubules
Name the structures that branch through the outer edges and centre of the mitotic spindle.
Polar microtubules
Name the structures that are sandwich between polar microtubules in the mitotic spindle.
Kinetochor microtubules
Name the drug used to test the significance of microtubules in mitosis.
Nocodazole
Name the force that microtubules exert when they pull on chromosomes.
A “polar ejection force”
Describe the contents of the contractile ring that forms near the cortex at the end of anaphase.
- myosin
- actin
- regulators
- actin-binding proteins
