Topic 1 cells Flashcards
prokaryotic
cells without a nucleus and are smaller and are a
simpler cell
eukaryotic
cells with a nucleus and are more complex such as all animal and plant cells also made of eukaryotic cells
prokaryote
a singled celled organism
nucleus
contains genetic material and controls the activities of the cell
cytoplasm
jelly like substance where the chemical reactions take place it also contains enzymes that control the reactions
cell membrane
holds the shape of the cell together and controls what enters the cell and what exits the cell
mitochondria
where the aerobic reactions take place respiration also transfers energy that the cell needs to work
ribosomes
where the proteins for the cells are created
cell wall
made of cellulose supports the cell and strengths it
vacuole
contains cell sap a solution of sugar and salts
chloroplast
where photosynthesis happens which makes the food for the plant
chlorophyll
a green substance found in chloroplast and absorbs the sunlight for photosynthesis
plasmids
rings of DNA
differentiation
the process when a cell becomes specialised for it’s job
stem cells
undifferentiated cells they can become any cell in the body
sperm cells
used for reproduction rounded head to penetrate the egg cell and a tail to swim to it has lots of mitochondria because it needs the energy to do its job enzymes in the head to digest through the egg cells membrane
nerve cells
used for rapid signalling carries electrical signals from one part to another in the body the cells are long to cover long distances this forms a network throughout the body
muscle cells
used for contraction cells are long so have space to contract contains lots of mitochondria for the energy needed to contract
root hair cells
used for absorbing water and minerals have a large surface area and look like a large hair sticking into the soil so they can absorb more water and minerals
phloem
transports food mostly sugars the transport goes both ways and is called translocation
xylem
takes up water made of dead cells joined together carries water and mineral ions which come from the roots, stem and leaves the water moved up through the plant and this is called transpiration system
chromosomes
coiled up lengths of DNA molecules chromosomes carry lots of genes and these give us our charactristics
chromosomes in a human
23 pairs of chromosomes one from the mother and one from the father
body cells
divide in multicellular organisms producing more cells and part of the cell cycle
mitosis
when cells divide to grow or replace old or damaged cells ends with two identical cells with 23 pairs of chromosome
cell cycle
before a cell divides it has to duplicate a number of mitochondria and ribosomes and increase the size of the cell
binary fission
the circular DNA replicate so the cells get bigger and the circular data move to the two poles of the cell the cytoplasm begins to divide and the new cell walls begin to form them it divides into two cells each has one circular DNA but has a random number of plasmids
stem cells locations
embryos have many and adults have them in their bone marrow
diseases cured by stem cells
diabetes, paralysed by spinal injuries because it can replace the bad genes with the good ones also they are being used for cloning
against stem cells research
requires embryos to be destroyed after extracting the stem cells
stem cells in plants
used to grow in the meristems as they are undifferentiated until they are needed so they can also create clones of themselves
diffusion
movement of particles from high concentration to low concentration happens in gases and liquids the bigger the difference in concentration(concentration gradient) the faster the diffusion is the higher the temperature also makes it diffuse faster
osmosis
the movement of water of molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration
active transport
the root hair cells have a large surface area so more minerals can be absorbed the concentration is greater inside the root hair cell so it is going from low concentration to high and is called active transport
active transport in the body
there is a low concentration of nutrients in the gut and a higher concentration in the blood when there is a higher concentration in the gut it will diffuse but if it is lower, then active transport needs to transport the nutrients as diffusion can’t
exchanging surfaces
how easily things move between organisms and its environment depending on the surface area to volume ratio
