Topic Three - Cell Cycle, Mitosis and Stem Cells Flashcards

Question

terminally differentiated

Answer 1

cells that have lost the ability to replicate

Answer 2

Prophase, metaphase, anaphase, telophase

Answer 3

The longest part of the cell's life cycle, the resting stage (cell isn't dividing) - DNA replication occurs - period of growth and development - cell grows, carriers out normal cell activities, replicates all other organelles - By the end of interphase the cell has two full sets of chromosomes and is large enough to begin the division process

Answer 4

1 Chromosomes condense and are more visible. The nuclear membrane (envelope) disappears. Centrioles have separated and taken positions on the opposite poles of the cell. Spindle fibers form and radiate toward the center of the cell.

Answer 5

DNA WRAPS AROUND PROTEINS (HISTONES) THAT CONDENSE IT.

Answer 6

2 Chromosomes line up across the middle of the cell. Spindle fibers connect the centromere of each sister chromatid to the poles of the cell.

Answer 7

3 Centromeres that join the sister chromatids split. Sister chromatids separate becoming individual chromosomes. Separated chromatids move to opposite poles of the cell.

Answer 8

4 Chromosomes (each consisting of a single chromatid) uncoil. A nuclear envelope forms around the chromosomes at each pole of the cell. Spindle fibers break down and dissolve. Cytokinesis begins.

Answer 9

the division of the rest of the cell (cytoplasm and organelles) after the nucleus divides. Animal cells - In animal cells the cytoplasm pinches in forming a cleavage furrow: Plant Cells - In plant cells, a cell plate forms creating a cell wall

Answer 10

g1 - cell size, nutrients, growth factors, DNA damage g2 - cell size, DNA replication mitosis - chromosome attachment to spindle

Answer 11

SKIN CELLS CALLED KERATINOCYTES SELF DESTRUCT IN AN ORDERLY AND PROGRAMMED MANNER CALLED APOPTOSIS THIS OCCURS EVERY 3 WEEKS, CAUSING YOU TO SHED LAYERS OF SKIN VERY OFTEN A HUMAN EMBRYO LOSES THE WEBBING IN BETWEEN ITS FINGERS AND TOES THROUGH THIS PROCESS

Answer 12

VERY IMPORTANT DURING DEVELOPMENT, SHAPING ORGANS AND TISSUES, TO REMOVE OLD CELLS OR IF A CELL HAS BECOME INFECTED CONTROLLED BY MANY GENES THAT PRODUCE ENZYMES THAT SHRED DNA INTO THOUSANDS OF FRAGMENTS THE MEMBRANE FORMS BLEBS MADE OF PLASMA MEMBRANE MACROPHAGES (WHITE BLOOD CELLS) ENGULF THESE AND RECYCLE THEM IT NORMALLY HAPPENS IN CELLS THAT HAVE BEEN AROUND IN THE BODY LONG ENOUGH THAT THEY'RE WORN OUT AND SO THEY NEED TO BE REPLACED BY NICE, NEW YOUNG CELLS WHEN THAT DOESN'T HAPPEN, IT CAN CAUSE CANCER SO APOPTOSIS CAN BE NORMAL, AND IN THE ABSENCE OF APOPTOSIS, THAT CAN LEAD TO CANCER TOO MUCH APOPTOSIS IN AN OTHERWISE NORMAL HUMAN BEING WILL RESULT IN A NUMBER OF SO-CALLED NEURODEGENERATIVE DISEASES WHERE CELLS DIE WHEN THEY'RE NOT SUPPOSED TO DIE

Answer 13

DNA controls all cell activities including cell division Some cells lose their ability to control their rate of cell division – the DNA of these cells have become damaged or changed (mutated) If the cell's apoptosis genes have been mutated then cell death will not occur These super-dividing cells form masses called tumours

Answer 14

cell division must be controlled, otherwise, cell growth will occur without limit (cancer)

Answer 15

(GENES THAT PROMOTE CANCER) IF MUTATED THEY CAN PRODUCE ONCOGENES → CANCER ANY CHANGE IN THESE GENES THAT ENHANCES THEIR FUNCTION CAN PROMOTE UNCONTROLLED CELL GROWTH AND CANCER.

Answer 16

TWO MAIN TYPES OF GENES THAT REGULATE THE CELL CYCLE THEY HAVE BEEN STUDIED BECAUSE THEIR FUNCTIONS ARE LINKED TO CANCER proto-oncogenes tumour suppressor genes

Answer 17

THEY NORMALLY KEEP THE CELL FROM DIVIDING TOO QUICKLY, LIKE BRAKES SLOWING A CAR DOWN. MOST OF THESE ARE MUTATED/SILENCED IN CANCER.

Answer 18

CHEMICAL MUTAGENS PHYSICAL MUTAGENS BIOLOGICAL MUTAGENS

Answer 19

THEY INTERFERE WITH DNA BY INTERRUPTING ITS STRUCTURE, SEQUENCE OR REPLICATION. IF THE MUTATION AFFECTS CELL CYCLE REGULATION GENES, THIS INHIBITS CHECKPOINTS AND CAUSES UNCONTROLLED CELL DIVISION.

Answer 20

PHYSICAL FACTORS INCLUDE ULTRAVIOLET LIGHT, X-RAYS AND NUCLEAR RADIATION CAN CAUSE MUTATIONS IN DNA. UV LIGHT IS ABSORBED AND DAMAGES DNA IN SKIN CELLS. OVEREXPOSURE TO THE SUN MAKES IT HARD FOR REPAIR MECHANISMS TO KEEP UP.

Answer 21

VIRUSES CAN CAUSE MUTATIONS OR IMPAIR CELL CYCLE REGULATION. SOME HAVE ONCOGENES THAT STIMULATE CELL DIVISION. SOME CAN INSERT THEIR DNA INTO HUMAN CELL CYCLE REGULATION GENES, CAUSING THEM TO LOSE CONTROL OF CELL DIVISION, LEADING TO CANCER. EG. HUMAN PAPILLOMAVIRUS.

Answer 22

cell cycle

Answer 23

THEN IT CREATES AN ‘ONCOGENE’ THAT SENDS MESSAGES TO THE CELL TELLING IT TO DIVIDE REPEATEDLY

Answer 24

THEN THE NORMAL MESSAGES TELLING THE CELL TO SLOW DOWN DIVISION ARE STOPPED, CAUSING DIVISION TO HAPPEN FASTER

Answer 25

cells become specialised through a process called differentiation once they have committed to a path way there is no turning back

Answer 26

undifferentiated cells that have the potential to replicate and differentiate into various tissues,

Answer 27

describes how many types of specialized cells a stem cell can differentiate into, they can be totipotent, pluripotent and multipotent

Answer 28

are found in the first few divisions of a zygote can differentiate into ALL cell types

Answer 29

are found in the inner cell mass of a blastocyst (128 cell embryo) can differentiate into any cells in the body except the placenta

Answer 30

are found in bone marrow or umbilical cords can differentiate into a limited number of cells related to their tissue of origin

Answer 31

1 - Embryonic stem cells (ESC) - taken from a 5-day-old embryo (blastocyst) - they keep their potency after multiple cell divisions - pluripotent - created to be destroyed 2- Adult stem cells (ASC) - undifferentiated cells found in tissues )brain, bone marrow, liver, fat) - multipotent - used to treat bone disorders and leukemia - come from patients' own body so they won't reject them

Answer 32

Differentiated cells can be treated and turned back into pluripotent stem cells

Answer 33

they can replace damaged cells in the body and treat diseases scientists can clone them, differentiate them and then give them to a patient - ASC - a blood disease - ESC - Damaged nerve cells there are high risks, rejecting them from someone else, virus contamination, ethical problems ESC

Topic Three - Cell Cycle, Mitosis and Stem Cells Flashcards

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