Flashcards in topic 1 (cell biology) Deck (35)
cells with a nucleus
cells without a nucleus
*everything in an animal cell plus:
job of nucleus?
controls all the activities in the cell
job of ribosomes?
these are where proteins are made in the cell
job of cell mem?
controls what goes in and out of cells
job of mitochondria ?
where respiration takes place
job of chloroplast ?
where photosynthesis takes place
job of permanent vacuole ?
contains cell sap and helps to keep plant turgid
job of cell wall ?
gives strength to the cell
(+cytoplasm,cell mem and cell wall)
replacement nucleus and hold the genetic material
small rings of DNA
image size /real size
uses light and lenses to produce an image (e.g nuclei)
uses electrons to form an image , it also has a higher magnification and resolution then a light microscope and lets us see much smaller things
body cells contain two of each chromosome and this is found in the nucleus. humans have 23 pairs
a type of cell division that results in two daughter cells each having the same number and kind of chromosomes
stages of mitosis
Interphase The cell spends most of its life in this phase. The DNA in chromosomes copies itself ready for mitosis.
Prophase The DNA in chromosomes and their copies condenses to become more visible. The membrane around the nucleus disappears.
Metaphase Chromosomes and their copies line up in the middle of the cell.
Anaphase Chromosomes and their copies are pulled to different ends of the cell.
Telophase New membranes form around the chromosomes at each end of the cell.
Cytokinesis The cell membrane pinches in and eventually divides into two daughter cells.
when does mitosis take place?
mitosis takes place when an organism repairs itself or during asexual reproduction
movement of molecules from an area of a high conc to an area of a low conc (e.g oxygen out and carbon dioxide in plants )
factors affecting rate of diffusion
difference in conc (conc gradient)
is the diffusion of water from a concentrated solution to a dilute solution through a partially permeable membrane
the movement of particles from an area of low conc to an area of high conc and this process does require energy
what is binary fission
the process by which bacteria divides into two every 20 mins
number of bacteria=2^(rounds of division)
differentiation / specialisation
cells change to become specialised for there job
-animal cells loose this ability at an early stage
-plant cells never loose this ability
examples of specialised cells
sperm cells = reproduction
nerve cells= rapid signalling
muscle cells= contraction
root hair cells= water and minerals
phloem and xylem =transporting substances
muscle cells contain protein fibers to help them contract