| where can you find the genetic information for an organism? | the nucleus |
| what is the genetic information in the nucleus called? | DNA |
| what is DNA in the nucleus organised into? | chromosomes |
| what is mitosis? | the process of cell division that produces two genetically identical daughter cells |
| describe stage one of mitosis | chromosomes replicate to become thicker visible pairs of chromatids, joined at centromeres |
| describe stage two of mitosis | the chromosomes (made of pairs of chromatids) line up along the equator of the cell, attached to spindle fibres. |
| describe stage three of mitosis | their pairs of chromatids are pulled apart by spindle fibres to opposite poles of the cell |
| describe stage four of mitosis | two new nuclei form around the chromatids, which are now called chromosomes |
| describe stage five of mitosis | after mitosis, the production of new nuclei, the cell cytoplasm becomes pinched off and two genetically identical daughter cells are formed |
| what is the purpose of cell division | produces new cells for growth and the repair of damaged tissues and replacement of dead or damaged cells. |
| define chromosome complement | number of chromosomes in an organism's cell |
| define haploid | one set of chromosomes |
| define diploid | two sets of chromosomes |
| what does mitosis maintain | diploid chromosome complement,
two matching sets of chromosomes are replaced during mitosis to produce more diploid cells |
| what is a stem cell | unspecialised animal cells involved in tissue growth and repair
they can divide in order to self renew and have the potential to become different types of cells |
| what is the multicellular organism hierarchy | cell > tissue > organ > system > organism |
| describe embryonic stem cell | can be obtained from the embryo at a very early age
have the potential to become any cell type found in the body |
| describe tissue stem cells | can be found in the body throughout life
have the potential to become only a few types of cell |
| what does specialisation of cells in multicellular organisms lead to? | the formation of a variety of cells, tissues and organs.
groups of organs work together to form systems. |
| what is a specialised cell? | cells designed to carry out a particular role in the body |
| why do cells become specialised in multicellular organisms? | to carry out different functions which allows organisms to function more efficiently |
| in what tissue can you find epithelial cells? | cheek epithelium |
| what are the specialised structural features of epithelial cells? | flat, irregular shape allows cells to form a loose covering layer which constantly replaced during wear and tear |
| what is the function of epithelial cells? | they protect mouth lining |
| in what tissue can you find red blood cells? | blood |
| what are the specialised structural features of red blood cells? | small size and biconcave shape present a relatively large surface area rich supply of haemoglobin present |
| what is the function of red blood cells? | uptake and transport of oxygen to living cells |
| in what tissue can you find white blood cells? | blood |
| what are the specialised structural features of white blood cells? | able to change shape sacs of microbe-digesting enzymes present in some types |
| what is the function of white blood cells? | destruction of invading microbes |
| in what tissue can you find motor neuron cells? | nerve tissue |
| what is the specialised structural feature of motor neuron cell? | axon (long insulated extension of cytoplasm) |
| what is the function of motor neuron cells? | transmission of electrical impulses |
| what is the specialised structural feature of sperm cell? | have tail |
| what is the function of sperm cell? | to help sperm swim towards the egg in the female reproductive tract |
| in what tissue can you find goblet cell? | ciliated epithelium tissue |
| what are the specialised structural features of goblet cell? | cup shape
able to produce mucus |
| what is the function of goblet cell? | secretion of mucus traps dirt and germs |
| in what tissue is the ciliated epithelial cell found? | ciliated epithelial cell |
| what specialised structural features do ciliated epithelial cell have? | hair like cilia that beat upwards |
| what is the function of the clilated epithelial cell? | sweeping of dirty mucus up and away from lungs |
| in what tissue can you find palisade mesophyll cells? | mesophyll |
| what is the specialised structural features of palisade mesophyll cell? | chloroplasts present; columnar shape
allows densely packed green layer to be presented to light |
| what is the function of palisade mesophyll cell? | primary region of light absorption and photosynthesis |
| in what tissue can you find spongy mesophyll cells? | mesophyll tissue |
| what are the specialised structural features of spongy mesophyll cells? | round shape allows loose arrangement in contact with moist air spaces for absorption of carbon dioxide |
| what is the function of spongy mesophyll cells? | secondary region of photosynthesis |
| in what tissue can you find sieve tube cell? | phloem tissue |
| what are the specialised structural features of sieve tube? | sieve plates and continuous stream of cytoplasmic strands (but no nucleus) |
| what is the function of sieve tube cells? | transport of soluble carbohydrates up and down the plant |
| in what tissue can you find companion cell? | phloem tissue |
| what is the specialised structural features of companion cell? | large nucleus in relation to cell size |
| what is the function of companion cells? | control of sieve tube functions |
| in what tissue can you find xylem vessel? | xylem tissue |
| what is the specialised structural features of xylem vessel? | hollow tube; wall strengthened by lignin
lignin deposited as rings or spirals allowing expansion and contraction |
| what is the function of xylem vessel cells? | support and water transport up the plant |
| in what tissue can you find root hair cells? | root epidermis |
| what are the specialised structural features of root hair cells? | long extension of an epidermal cell presenting a large surface area in contact with soil solution |
| what is the function of root hair cells? | absorption of water and mineral salts |
