Cell biology Flashcards
cell
Structural and functional
unit of living organisms
* All human cells originate
from a single fertilized egg
Development involves cell
replication & specialization
four main types of tissue in humans
connective tissue
epithelial
muscle
nervous tissue
what is epithelial tissue
Epithelial cells make up the epithelium. The cells come
from the surfaces of your body, like skin, digestive tract and
organs
how is cell diversity determined
genes -> proteins -> determined cell structure and function
each cell expresses only a subset of its genes
how big are cells (4)
cell sizes range from 5 to 100 micrometers
average cell nucleus is around 5 micrometers in diameter
micrometer = 1 - 1,000,000 of a meter
and 1 - 1000 of a millimeter
how small is a nanometer
1 nanometer = 1000 micrometers
viewing power of the human eye
down to 0.2mm
viewing power of light microscope
down to 0.2um
viewing power of the electron microscope
down to 0.2nm
what is mitosis needed for (4)
growth and repair
remember this
some cells are just too specialised to divide, and some cells divide very rapidly
explain G1 (first gap phase) of cell cycle (4)
growth and normal metabolic roles
explain S (synthesis phase) of cell cycle
DNA replication
explain G2 (second gap phase) of cell cycle (4)
growth and preparation for mitosis
what is interphase made up of
G1 - 2 - G2
In a normal human cell there are 46 chromosomes, also
called 23 pairs of chromosomes
In a cell in S phase, each chromosome doubles it’s DNA,
forming 2 chromatids, joined by a centromere
A DIPLOID cell has the full complement of chromosomes, a
HAPLOID cell has half
G1 phase (gap phase 1)
- growth & normal
cellular activity
S phase (synthetic phase)
- DNA replication
- 6-8 hours
G2 phase (gap phase 2)
brief, final preparation
for cell division
3-4 hours
prophase (4) (first part)
chromosomes condense and become visible
- nuclear membrane disappears
- mitotic spindle starts to form from centrioles
metaphase
chromosomes line up on equator
the spindle is fully formed
anaphase
chromosomes split at centromeres
Telophase
decondensation of chromatin
reformation of nuclear envelope
- cytokinesis
plasma membrane of cell
outer boundary of the cell, lipid bilayer (polar/non-polar) + proteins
highly dynamic and fluid structure
how is the phospholipid bilayer fluid in nature
because of chlorestrol, which is imbedded within the phospholipid bilayer, gives it a lot of its fluidity
Control centre of the cell
- control is mediated via
the DNA
nuclear envelope
chromatin
nucleolus
nuclear envelope
- double-membrane
- nuclear pores
- outer membrane is
continuous with Rough ER
chromatin (4)
- DNA / histone proteins
nucleolus
- produces ribosomes
rough ER
- cisternae/lamellae (sheets)
- studded with ribosomes
(protein/RNA subunits) - Site of protein synthesis