Cellular division and organisation Flashcards
(24 cards)
Interphase
DNA is replicated and checked Organelles replicated ATP content increased Cell increases in size Largest part of cell cycle
Prophase
Chromosomes condense (visible) Centrioles make spindle (from fibrous proteins) Nuclear envelope breaks down
Metaphase
Chromosomes line up, middle of cell
Spindle attaches to centromeres
Anaphase
Centromeres divide, chromatids separated
Spindle contracts, chromatids pulled to poles
Telophase
At poles chromatids uncoil=chromosomes 2 nuclear envelopes form 2 genetically identical daughter cells Same number of chromosomes as parent cell (cytokinesis next stage)
Mitosis used for
Growth of organism
Tissue repair
Old cell replacement
Asexual reproduction
Define cell cycle
A continuous process, the events as one parent cell divides to produce two new daughter cells.
Define differentiation
The ability of a cell to specialise to for a particular type of cell
Define stem cell
Cells that aren’t specialised or differentiated, maintaining the capacity to undergo mitosis and differentiate into a range of cell types
Stem cells in humans and plants and what they differentiate into
Animal (bone marrow) erythrocytes and neutrophils
Embryonic, anything?
Plant (meristem tissues) cambium into xylem and phloem
Budding in yeast
Asexual reproduction, mitosis One nucleus moves to one side of cell Cell wall bulges Nucleus moves into bulge Bulge constricts, separate daughter cell
Meiosis produces cells that are
Not genetically identical
Gametes
Haploid
Erythrocyte specialisation
Carry oxygen in blood Small, flexible (fit through capillaries) Packed with haemoglobin (bind with O2) No nucleus (more space Hb) Biconcave shape (large SA take up O2)
Neutrophil specialisation
Engulf, digest foreign matter or old cells
Flexible shape (move through tissues)
Lobed nucleus (move through membranes)
Many ribosomes (make digestive enzymes)
Many lysosomes (hold enzymes)
Many mitochondria (release energy for activity)
Well-developed cytoskeleton (enable movement)
Membrane-bound receptors (recognise materials destroy)
Sperm cell specialisation
Carry paternal chromosomes to egg Flagellum (rapid movement) Acrosome (digest egg surface) Small (easier movement) Many mitochondria (release E for rapid movement)
Epithelial cell specialisation
Surfaces
Squamous, flat thin (large area, short diffusion distance)
Ciliated (move mucus)
Cuboid (barrier)
Many glycolipids+glycoproteins in plasma membrane (hold cells together as a surface)
Palidade cell specialisation
For photosynthesis Elongated (many chloroplasts) Many chloroplasts (absorb most light) Cytoplasmic streaming (move chloroplasts, less damage) Starch grains (store photosynthesis products)
Root hair cells
Absorb water and mineral ions form soil
Long extension (increase SA)
Active pumps in plasma membrane (absorb mineral ions active transport)
Thin cell wall (reduce barrier for ions and water movement)
Guard cell specialisation
Control stomatal opening
Active pumps in cell surface membrane (move mineral ions in/out, alter water potential)
Unevenly thickened wall (cell change shape as more turgid)
Large vacuole (take up water, expand open stomata
Homologous pair of chromosomes
Same shape and size
Centromere same position
Same genes same positions
Tissue
Collection of cells work together perform a particular function
Eg ciliated epithelium
Xylem
Phloem
Organ
Collection of tissues working together to perform a common function
Organ system
Two or more organs working together to perform a life function
Cell signalling
Communication and coordination between cells
The shape of the signal molecule is complementary to the shape of the receptor molecule on the target cell.
