cell biology and genetics 2 - neil

Question 1

what is an organism?

Answer 1

living being

Question 2

what are the properties of a cells

Answer 2

self-contained and self-maintaining entity
-take in nutrients and convert these nutrients into energy
-reproduce as necessary

Question 3

what are the 2 types of cells

Answer 3

singular or multicelluar

Question 4

what are singular cells

Answer 4

Function and survive more or less independently, through colonial forms with cells living together

Question 5

what are multicelluar cells >

Answer 5

Cells are specialized and do not generally survive once separated.

Question 6

All cells have for at some part of their life either…

Answer 6

Nucleus or Nucleoid

Question 7

describe prokaryotic cells

Answer 7

found only in single-celled and colonial organisms

In the three-domain system of scientific classification, prokaryotic cells are placed in the domains Archaea and Eubacteria

Question 8

describe eukaroytic cells

Answer 8

Possess have organelles with their own membranes

mainly multiceulluar

(The multicellular kingdoms, i.e. Animalia, Plantae and Fungi, are all eukaryotic.)

Question 9

what are the 2 major phases of the cell cycle?

Answer 9

Mitosis
Interphase

Question 10

Cell Fate is satisfied by one of the 3 D’s

Answer 10

Divide
Differentiate
Die

Question 11

describe mitosis

Answer 11

Genetic Division
Preceded by Interphase
Preceded by Interphase
Comprised of 5 phases

Question 12

describe interphase?

Answer 12

Cell increases in size
DNA is replicated (S Phase) generating two chromatids ( = chromosome)
Centrosome is duplicated

Question 13

describe centrioles

Answer 13

Hollow cylindrical organelle

Walls are composed of 9 triplets of microtubules

Important in cell division organising the spindle upon which the chromosomes are pulled apart

Question 14

describe prophase?

Answer 14

Duplicated DNA Condense to form 2 sister Chromatids

DNA becomes visible to the light microscope

Centrioles begin to move to opposite ends of the cell and fibres (Asters) grow and extend from the centromere

Cyclins and Cyclin Dependent Kinases (CDK) are activated

CDK phosphorylate nuclear proteins resulting in the breakdown of the NM

End of Prophase the majority of Nuclear membrane (80%) is broken down through phosphorylation and barrier between nucleus and cytoplasm is eliminated

Question 15

pro - meaphase

Answer 15

Prometaphase starts with complete dissolution of NM

Formation of the proteinaceous spindle structure (bird cage)

Proteins attach to the centromeres creating the Kinetochores

Kinetochores attach to the spindle microtubules and begin to undergo active movement

Question 16

metaphase?

Answer 16

Microtubules form spindle pole body

Spindle fibres align chromosomes along equator (middle) equator of the nuclear remnants

Alignment along the metaphase plate is checked for correct positioning

2 members of sister chromatid pair attach to a microtuble originating on the opposite spole of a spindle

Question 17

anaphase?

Answer 17

Sister chromatids move outwards

Separation results in the formation of two daughter chromosomes

Pulled apart and slowly move towards the spindle pole

Kinetochore μtubules get shorter and spindle pole moves outward

Results in chromosome separation

Question 18

telophase?

Answer 18

Chromatids arrive at the opposite ends of cell (each pole)

New NM form around daughter nucleii through the action of Phosphatases which remove the phosphate groups generated by the CDKinases (cf Prophase)

Chromosomes begin to disperse and lose definition under microscope

Spindle fibres begin to disperse

Contractile ring begins to form

Beginning of Cytokinesis

Question 19

cytokensis?

Answer 19

Not a phase of Mitosis (Mitosis is genetic segregation)

Cytokinesis is cellular segregation

Cytoplasm divided into 2 by a contractile ring of Actin and Myosin Filaments

End of cell division generating two daughter cells

Each cell contains an individual and identical nucleus