Cell reproduction Flashcards
(20 cards)
Cell Cycle stages - Interphase
G1 Phase - cell growth
S Phase - DNA Replication
G2 Phase - cell prepares for division
Cell cycle - M phase & C phase
M phase -mitosis, nucleus divides
C phases - cytokinesis
Mitosis stage 1
Prophase - chromatin threads condense becomes visible, cellular membrane disappears, spindle fibers begin to form attach to centromeres of chromosomes, move to opposite poles
Mitosis stage 2
Metaphase - chromosomes move to centre of cell equator (metaphase plate), the centrioles are located at opposite sides of the cell
Mitosis stage 3
Anaphase - spindle fibers shorten and pull the centromeres of chromosomes to opposite poles, separating the sister chromatids, there is a complete identical set of maternal and parental chromosomes
Mitosis stage 4
Telophase - decondenses, two new nuclear membranes form, spindle fibres disappear, cell elongates and cleavage furrow forms ready for cytokinesis
Meiosis 1 (Prophase 1)
Prophase 1 - chromatids condense, maternal and parental attached to each other and pair up (CROSSING OVER), consists of two sister chromatids, nuclear membrane & nucleus disappears, spindle fibres begin to form, attachment to centromes of chromosomes and move opposite poles
Meiosis 2 (Metaphase 1)
Metaphase 1 - maternal and parental line-up on metaphase plate in a homologous pairs (INDEPENDENT ASSORMENT) - line-up in pairs independently of every other pair, resulting in RANDOM ASSORTMENT in 4 daughter cells
Meosis 3 (anaphase 1)
Anaphase 1 - spindle fibres shorten pulling centromere, each member of homologous pairs move to each end of cell resulting in a random combinations of maternal and parent
Meiosis 4(telophase 1)
Telophase 1 new cellular membrane spindle fibres disintegrate
Meiosis 5(cytokinesis 1)
Cytokinesis 1 - cytoplasm separates = 2 haploid cells, one chromosome from each
Meiosis 6 (prophase 2)
Prophase 2 - chromatids condensers you spindle fibres nuclear membrane disintegrates
Meiosis 7 (metaphase 2)
Metaphase 2 - Individual chromosomes light up along the metaphase plate in random order spindle fibres attach to centromere
Meosis 8 (anaphase 2)
Anaphase 2 - sister chromatids separate at centromeres as spindle fibers shorten and move to opposite poles
Meiosis 9 (telophase 2)
Telophase 2 - chromosomes unwind loosen, reform chromatin, 4 nuclear membranes membranes
Meiosis 10 (cytokinesis 2)
Cytokinesis 2 - separate cytoplasm full non-identical haploid cells
animal cells - cleavage furrow
plant cell - new cell wall plates
Binary Fission
-prokaryotes cells
aesexual reproduction
1Prior - chromosomes tightly coiled
2Replication - genetic material and plasmids replicate and separates 3Elongation - replicated materials attached to cell membrane are pulled opposite side in cell as it elongates 4Cell Wall - New cell wall starts to develop
5Cytokinesis - new cell fully developed
6Final - cell separate form two identical daughter cells and become tightly packed together
Apoptosis in multicellular organisms
Apoptosis the orderly programmed self-destruction of cells
- vital for the development and shaping of organs and tissues
- cause cells to die at a specific stage of development
Eg. Tadpoles tail as it becomes a frog Humans loosing webbing between fingers and toes
Phenotype
Is an observable trait
How does environment influence gene activity
Genes cannot dictate the structure of an organism themselves environment helps.
E.g. twins trait may look different even though they might have the same genre and protein for trait
Due to external factors: pH level, temp, food availability, light/wind exposure
Eg. With plants some flower petal colours determined by the pH in the soil
Internal Factors: action of hormones
Eg. Human hormone realeased triggering puberty - gondotrophin
