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29 Cards in this Set
- Front
- Back
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The Cell Cycle |
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Binary Fission |
Asexual Reproduction Process in Prokaryotes Genetically Identical Single Circular Chromosome Replicated Salmonella "Prokaryotic cells arise through the division of existing ones" |
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Generation Time |
The time required for a bacterial cell to divide or a population of bacterial cells to double. |
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Mitosis (2) |
Interphase G1 - cell contents duplicated - metabolic changes (to prepare for cell division) - cell growth and development G1 Checkpoint Checks: - cell size and sufficient nutrients If all good then go signal initiated |
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Mitosis (3) |
Synthesis Stage - replication of DNA (Human = 46 somatic (body cells)) - each chromosome now consists of two sister chromatids |
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Mitosis (4) |
G2 - metabolic changes assemble the cytoplasmic materials necessary for mitosis and cytokinesis - cell checks duplicated material for error and then repairs them - rapid cell growth and protein synthesis G2 Checkpoint Checks: cell size, replication has been successful, proteins required have been synthesised - if all good then go |
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Mitosis (5) |
Prophase - occupies about 1/2 Mitosis Early - DNA condenses into distinct chromosomes - nuclear membrane breaks down - centrosome duplicates itself and migrates to opposite ends of cells Late - chromosomes appear as two chromatids held by centromere - spindle fibres form the mitotic spindle |
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Mitosis (6) |
Metaphase - spindle fibres attach to and organise the chromosomes - chromosomes align themselves along the equator - some spindle fibres span the cell Metaphase Checkpoint - pass if all chromosomes are attached to mitotic spindle |
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Mitosis (7) |
Anaphase - shortest of Mitosis - spindle fibres shorten or lengthen - centromeres divide and sister chromatids pull apart Telophase - two new nuclei form and furrow forms in midline Cytokinesis - division of cytoplasm - two separate daughter cells |
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Mitosis (1) |
- an existing cell (parent cell) divides into two daughter cells - no change in chromosome number - daughter cells identical to parent cell - occurs in tissues |
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Mitosis (8) |
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Plant Propogation |
Vegetative Propagation - produces new, genetically identical individuals (clones) without the need for seeds or spores - plants spread quickly when conditions are favourable - enable successful varieties to be propagated indefinitely |
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Vegetative Structures (1) |
Tubers - Potatoes (stem), Dahlias (root) - swollen part of underground stem or root - modified for food storage - can give rise to new individuals Bulbs - Daffodils - a shoot compressed into a shortened form - fleshy storage leaves are attached to a stem plate and form concentric circles around growing tip - new roots form from bottom stem |
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Vegetative Structures (2) |
Corm - Cyclamen, Crocus - food stored in stem tissue - look like bulbs except in centre is a mass of homogeneous tissue Rhizomes - Ginger - food stored in horizontal underground stem - thick fleshy or woody -bear nodes with scale or foliage leaves and buds - growth occurs at buds or nearby nodes |
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Propagating from Cuttings |
Cuttings - sections of parent plants which are removed and grown as new individuals (clones) - plant hormone auxin accumulates at the base of the stem triggering the formation of roots - adding synthetic auxins to the end of the cutting promotes greater root development |
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Grafting - Apple Trees |
- the joining of the tissues of one plant to another (usually a variety of the same species) - important horticultural technique (fruit plants) - plant can have characteristics not full present in either parent plant - can produce plants with desirable characteristics quickly without having to breed |
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Grafting - Process |
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Micropropagation |
- the propagation of multiple plants from one piece of plant tissue - used for rapid multiplication of commercially important plant varieties with superior genotypes - used for recovery for endangered species - differentiated plant cells are totipotent - very labour intensive - affected by factors - composition of cultural media, selection of original plant material, hormone levels, lighting and temperature |
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Spores |
- asexual reproductive units produced for dispersal - usually asexual and haploid - common in fungi |
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Budding |
- bud grafting - used to convert one plant (rootstock) into another plant type with desirable characteristics - new individual develops from some generative anatomical point of the parent organism |
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Meiosis (1) |
- result in 4 genetically unique daughter cells - production of gametes - egg and sperm (makes gamete cells) - gametes are haploid (n) (23) because they contain half the DNA of a normal body cell Occurs ANIMALS - ovaries and testies PLANTS - ovary and anther |
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Meiosis (2) - How it occurs |
Humans |
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Meiosis (3) |
2 Divisions - first reduction division, second same as mitosis Meiosis 1 - halves the number of chromosomes (separates the pairs of homologous chromosomes) Meiosis 2 - sister chromatids are split |
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Meiosis (4) - Process |
Interphase - cell between periods of meiosis - cell grows and carries out required functions - chromosome material is loosely coiled 'threads' called chromatin - centriole duplicates itself - cell has 4 copies of each DNA molecule (2 in each chromosome) |
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Meiosis 1 (1) |
Prophase 1 - a perfect replica of DNA molecule within each chromosome is created - two identical chromosomes from mother and two from father - individual replicated chromosomes become visible - spindle fibres begin to form |
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Meiosis 1 (2) |
Metaphase 1 - line up on spindle at equator in homologous pairs (spindle fibres attach to centromere) - orientation on equator is random Anaphase 1 - chromosomes move apart from one another along the spindle fibre to opposite ends - still double stranded and has two sister chromatids - separates homologous chromosomes into two different cells so each will have only one member of homologous pair (haploid) |
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Meiosis 1 (3) |
Telophase 1 - spindle fibre disintegrates Cytokinesis - cell splits *TWO CELLS CREATED* - half the number of chromosomes compared to original |
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Meiosis 2 |
- exactly the same as mitosis - resulting cells have the same number of chromosomes as original cell |
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Meiosis 2 (1) |
Prophase 2 - two cells with two chromosomes |
