Mitosis Flashcards
Genetics are…
the study of heredity(the passing on of traits from parents to offspring) and variation
Organisms store genetic material in…
Chromosomes
Chromosomes contain the molecule…
deoxyribonucleic acid (DNA)
Each DNA molecule contains thousands of…
genes
Chromosomes are found in..
the nucleus in eukaryotes
Chromosomes found in sets of 2 are called..
diploids(2 copies)
cells that have half the normal number of chromosomes are called…
haploid
Some cells can contain 3 or more copies of DNA, these are called..
Polyploids
Mitochondria and chloroplasts also have small amounts of DNA
Asexual reproduction
Production of offspring from a single parent: genetically identical to parent
Examples: binary fission, fragmentation
Advantages and disadvantages of asexual reproduction
Advantages:
- Don’t need to seek a mate
- Offspring will have the exact same DNA(less chances of problems)
Disadvantages:
-Invariable offspring which means that if the environment changes, individals may no longer be well adapted
-no genetic diversity
Sexual reproduction
Production of offspring from the fusion of 2 sex cells: genetically unique from its parents
Advantages and disadvantages of sexual reproduction
Advantages:
- Offspring are not identical to parents or to each other
-Variability means some individuals may be better able adapt and survive than their parents were
Disadvantages:
- Need to have different sexes, mating calls or dances
- Sex is biologically “costly” - attracting a mate can also attack predators (brightly coloured peacock)
The cell cycle is comprised of the…
interphase, mitosis, and cytokinesis
During interphase chromosomes exist as…
chromatin
Each chromosome is duplicated in..
interphase
Interphase
-Cell isn’t actively dividing
-All regular metabolic activities occurring
-Chromosomes not visible(chromatin)
-Dna replication happens during “S” phase of interphase, this results in sister chromatids attached with a centromere
Prophase
-Chromosomes become visible as they shorten and thicken
-In animal cells, structures called centrioles move to opposite ends of the cell and provide attachment for spindle fibres
-nuclear membrane veins to disappear
Metaphase
Spindle fibres are attached to centromeres and move sister chromatically towards equatorial plate
Anaphase
-Centromeres divide and the chromatids, now daughter chromosomes, move to opposite poles of the cell
-If mitosis proceeds correctly, the same number and type of chromosomes will be found at each pole of the cell
Anaphase
-Centromeres divide and the chromatids, now daughter chromosomes, move to opposite poles of the cell
-If mitosis proceeds correctly, the same number and type of chromosomes will be found at each pole of the cell
Telophase
-Chromosomes reach opposite sides of the cell and lengthen(chromosome —> chromatin)
-Spindle fibres dissolve
- Nuclear membrane forms around each set of chromatin
-2 daughter cells are now present
Cytokinesis
-In animal cells cleavage furrow develops, pinching off the cell into two
-In plant cells, a cell plate forms into a new cell wall
