Cell Division & Stem Cells Flashcards
What does the word homologous mean
Two chromosomes with the same genes at the same position
Each cell contains (how many) pairs of chromosomes
23
A cell that has pairs of chromosomes is said to be (what)
Diploid
What is cell division for
-growth
-replace worn out cells
-repair damaged tissue
What are the advantages of being multicellular
-can grow larger
- differentiation means cells can become specialized to perform different functions
-become more complex (e.g develop organ system)
When does cancer occur
When mitosis becomes uncontrolled. Normal cell division is controlled by genes to stop and start correctly
When does a tumor form
When cancer cells keep dividing. When a tumor gets large enough to get its own blood supply and starts to spread it has become malignant
What are gametes
Sex cells.
How many chromosomes do cells formed by meiosis have.
Half the number of a body cell, They are haploid.
Features of meiosis
-Cell divides twice, forming four gametes
-gametes are genetically different from each other
What is the difference between mitosis and meiosis
-cell divides once in mitosis , cell divides twice in meiosis
-2 cells in mitosis, four in meiosis
-half the chromosomes in meiosis
-mitosis for new body cells, meiosis for sex cells
-mitosis in all parts of the body, meiosis in reproductive organs
What is the difference between mitosis and meiosis
-cell divides once in mitosis , cell divides twice in meiosis
-2 cells in mitosis, four in meiosis
-half the chromosomes in meiosis
-mitosis for new body cells, meiosis for sex cells
-mitosis in all parts of the body, meiosis in reproductive organs
What is a stem cell
Undifferentiated cell that can be a specialized cell
What two things can stem cells do
self renewal
Maintains stem cell pool
specialised cell
Differentiation replaces dead or damaged cells
What can embryonic stem cells do
Can make all of the different types of cell in the body
