Scince Bio Quiz Flashcards
Cell theory
- All living things are made up of one or more cells
- The cell is the simplest form of life
- All cells come from other living cells
Prokaryotes
-simplest living things
-single celled
-lack of nucleus (no true nucleus)
-eg. archaea and bacteria
Eukaryotes
-more complex organisms
-complex systems, organized
-have a well defined nucleus
-eg. plants, humans, animals, etc.
Cytoplasm
-suspends all organelles
-mostly made up of water
-can turn into jelly form if not enough water present
Cell membrane
-flexible, double layered
-supports the cell
-semi permeable-> allows certain substances to go in and out like water
Nucleus
-spherical structure
-brain of the cell-> control the cell
-contains the DNA
Mitochondria
-powerhouse of the cell
-makes energy/ cellular respiration (glucose +oxygen -> CO2+water+energy)
ER
-3D tube network
-transports materials through the cell
-dots on it called ribosomes (where protein is made)
-dot = rough ER | non-dot = smooth ER
Golgi body
-looks like a stack of flattened pancakes
-collects materials to be removed from the cell
-secretes mucus
Vacuoles
-enclosed compartment containing water and materials
-plant-> storage, makes turgid, 1 big one
-animals-> storage, very small
Cell wall
-found outside the cell membrane
-rigid but porous; made of cellulose
-provide support and protection
-only in plant cells
Chloroplast
-contains chlorophyll and gives leaves their green colour
-absorbed light energy to use in photosynthesis (6CO2+6H2O -> C6H12O6 + 6O2)
Asexual reproduction
-single celled organisms divide and only one parent is involved
-offspring is exacts genetic copy
-advantage-> can take over very quickly
-dis-all has same flaws so can be killed just as quick as produced
Sexual reproduction
-multicellular organisms dive and two parents are involved
-offspring inherits characteristics from both parents
-advantage-> can adapt to different situations
-dis-> need to find a partner which depending on the situation can be very hard
Stages of mitosis
-interphase
-prophase
-metaphase
-anaphase
-telophase
-cytokinesis
Interphase
the stage of the cell cycle that occurs before mitosis and prepares the cell for division. During this phase, the cell grows and DNA is replicated
Prophase-separate DNA
-DNA condenses and becomes visible under a light microscope as chromosomes
-duplicated chromosomes are called sister chromatids and held together by centrosome
Metaphase - organize DNA
-chromosomes line up in the middle of the cell through the help of spindle fibres
-makes one band
Anaphase
-Sister chromatids move away from the centre by spindle fibre attaching to the centromere
-chromatids now called daughter chromosomes
-makes two lines
Telophase- makes new nucleus
-daughter chromosomes stretch out and become thinner no longer visible
- new nuclear membrane forms around each group of daughter chromosomes
-two curved lines far apart
Cytokinesis
-final stage of mitosis
-cytoplasm divided producing two identical daughter cells
-in plant cells a plate forms between the two cells
-in animal cells the cell membrane is pinched in the middle to separate
What is cancer?
A disease caused by uncontrolled division of abnormal cells. Cancer cells are very rigid and oddly shaped. Unlike normal cells cancerous cells necrosis gene is damage meaning that mitosis continues uncontrollably. Meaning there is nothing stoping them from continually dividing. They will clump together making a cancerous tumour. If left for too long it can metastasize meaning that it will spilt off and continue infecting.
Cell inhibition
When cells multiply only until they touch another cell (no crowding)
-cancer cells do not show contact inhibition
