2.1 cells tissues and organs
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What is the specialisation of animals cells?
a process in which cells can develop a specific function to which they are suited.
give examples of how a red blood cells structure helps it carry out its function.
red blood cell • haemoglobin to carry oxygen-oxyhaemoglobin • biconcave shape to increase surface area to contain more haemoglobin • small in size to fit through blood vessels • no nucleus for more space for haemoglobin
give examples of how a nerve cells structure helps it carry out its function.
• size-can be very large to carry signals long distances • shape-can connect with other nerve cells • myelin sheath-keep electrical signals in
give examples of how the structure of the sperm cell helps it carry out its function
• tail-swim to fertilise the egg - many mitochondrion to be able to have the energy to swim
what is the levels of organisation in animals?
cells->tissues->organs->systems cells form tissues, different tissues forming organs, organs working together to form systems.
what is the specialisation of plant cells?
a process in which cells develop a specific function to which they are suited
give examples of how a xylem cells structure helps it carry out its function.
• lignin rings to strengthen the structure - hollow tube of dead cells to transport water
give examples of how a phloem cells structure helps it carry out its function
• sieve plates allow sugars to move from one cell to the next • companion cell
What is the levels of organisation in animals?
cells->tissues->organs->systems cells form tissues, tissues form organs, organs work together to form systems.
what is the definition of a tissue?
groups of specialised cells that carry out particular functions.
What is the process of mitosis?
• chromosomes become visible in a diploid parent cell • chromosomes duplicate and become two chromatids joined by a centromere • chromosomes line up at the equator and spindle fibres attach to each pair of chromatids • Spindle fibres shorten and pull the chromatids apart. . The chromatids move to the opposite poles of the cell. • 2 new nucleuses form around each group of chromatids and the cytoplasm divides. • 2 new daughter cells are produced. Each cell has the same number of chromosomes as the original cell.
what is the first stage of mitosis?
the chromosomes become visible in a diploid parent cell.
what is the second stage of mitosis?
chromosomes duplicate and become two chromatids joined by a centromere.
what is the third stage of mitosis?
chromosomes line up at the equator and spindle fibres attach to each pair of chromatids
what is the fourth stage of mitosis?
spindle fibres shorten and pull the chromatids apart. The chromatids move to the opposite poles of the cell.
what is the fifth stage of mitosis?
2 new nucleuses form around each group chromatids and cytoplasm divides.
what is the sixth stage of mitosis?
2 new daughter cells are produced. Each cell has the same number of chromosomes as the original cell.
why does the daughter cell need to be the same as the parent cell?
• chromosomes carry genes which are stretches of DNA • each gene codes for one protein • the number of chromosomes that a species of animal or plant possesses is the chromosome complement • in humans the chromosome compliment is 46 • losing any chromosome would would mean a loss of genetic information and the cell would not function correctly
what is the chromosome compliment?
the number of chromosomes that a species of animal or plant possesses.