topic 1 - cell biology Flashcards
what is the function of a nucleus
contains DNA and controls the activities of the cell
what is the function of the cell membrane
controls what enters and leaves the cell
what is the function of the cytoplasm
where cell activities and reactions happen
what is the function of the mitochondria
provides energy from aerobic respiration
what is the function of ribosomes
make proteins- site of protein synthesis
what is the function of chloroplasts
where photosynthesis occurs - only found in plant cells
what is the function of the vacuole
used to store water and other chemicals as sell sap - only found in plant cells
what is the function of a cell wall
strengthens and supports the cell (made of cellulose in plants and peptidoglycan in bacteria cells)
what is a DNA loop
a loop on DNA not in a nucleus
what is the function of plasmids
a small circle of DNA, may contain genes associated with antibiotic resistance
how are sperm cells specialised
- streamlined head and long tail to aid swimming
- many mitochondria which supplies energy allowing the cell to move
- the acrosome (top of the head) has digestive enzymes which break down the outer layers of membrane of the egg cell
how are nerve cells specialised
long to cover more distance, branched connections at their ends to connect to other nerve cells and form a network throughout the body
how are muscle cells specialised
long so they have space to contract, contain lots of mitochondria to generate the energy needed for contraction
how are root hair cells specialised
large surface area meaning more water can move in, mitochondria to provide energy from respiration for active transport
what is differentiation
the process by which a cell changes to become specialised for its job
what are stem cells
undifferentiated cells that can differentiate into different types of cells
what are the two types of stem cells
embryonic and adult
what are embryonic stem cells
found in early human embryos, they have the potential to turn into any kind of cell
what are adult stem cells
only found in certain places, like bone marrow. they cant turn into any cell type at all, only certain ones such as blood cells
why are embryonic stem cells useful in medicine
they could be used to replace faulty cells in sick people, you could make insulin- producing cells for people with diabetes or nerve cells for people paralysed by spinal injuries etc
what is therapeutic cloning
a type of cloning where an embryo could be made to have the same genetic information as the patient. this means that the stem cells produced from it would also contain the same genes so wouldn’t be rejected by the patients body if used to replace faulty cells
why are some people against stem cell research
they feel that human embryos shouldn’t be used for experiments since each one is a potential human life
why can stem cells produce identical plants and what is it used for
- stem cells found in meristems
- through the plants entire life, cells in the meristem tissues can differentiate into any type of plant cell
- these stem cells can be used to produce clones of whole plants quickly and cheaply
- they can be used to grow more plants of rare species
- they can also be used to grow crops of identical plants that have features desired by farmers (e.g disease resistance)
how many copies of each chromosome do body cells normally have
2 - one from the organisms “mother” and one from its “father”
