cell structure and functions cell structure and functions animal cells 1. cell membrane 1. cell...
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Cell Structure and FunctionsCell Structure and FunctionsAnimal cells
1.1. Cell Cell structures membrane membrane
phospholipid bilayers and proteins
functions: semi-permeable membranes, allow
some molecules to go in or out, but do not allow
others to go in or out.
transport: active, passive and facilitated transport.
endocytosis V.S. exocytosis
2.2. Cellular appendagesCellular appendages
cilia or flagella – for movement.
Animal Cell StructureAnimal Cell Structure
Animal Cell StructureAnimal Cell Structure
How do molecules get into cells?
Phagocytosis
Pinocytosis
U-tube Osmosis
(a) Isotonic
Water concentration inside the cells is equal to the water concentration in the fluid surrounding the cell. Therefore, there is no net movement of water either into or out of the cell.
(b) Hypertonic
Water concentration in the surrounding medium is lower than it is in the cell. Water moves out of the cells and the cells shrivel (crenate).
(c) Hypotonic
Water concentration outside the cell is greater than it is inside the cell. Water moves into the cell, which swell and sometimes burst – a process called lysis.
Fluid Mosaic Model
Phospholipid Structure
3.3. MitochondriaMitochondria power house of the cells cellular respirations take place
6O2 + C6H12O6 6CO2 + 6H2O + 38ATP double membrane, inner membrane fold to
increase surface area. genetic material of its own.
4.4. LysosomeLysosome hydrolytic enzymes, e.g. lipase, proteinase,
amylase etc. phagocytosis remove the injured cells molecules turn over
5.5. RibosomeRibosome
large subunit (60S) and small unit (40S)
rRNA and proteins
for protein synthesis
6.6. Endoplasmic reticulum (E.R.)Endoplasmic reticulum (E.R.)
communication and transport system in the cell
rough E.R. (with ribosome attached): protein synthesis
smooth E.R. (no ribosome attached): lipid synthesis
7.7. Golgi complexGolgi complex
packaging center
combine different organic molecules for secretion
8.8. CentriolesCentrioles
a pair, perpendicular to each other regulate cell division
9.9. NucleusNucleus
double membrane structure
the brain of the cells
control all the activities in cells
genetic materials in chromosomes
nucleolus: a mass of RNA
Cell CycleCell Cycle Cell Cycle Cell Cycle
GG1 1 : Gap one, before DNA : Gap one, before DNA
synthesissynthesis
S : DNA synthesisS : DNA synthesis
GG2 2 : Gap two, after DNA: Gap two, after DNA
synthesissynthesis
M : prophase, metaphase, M : prophase, metaphase,
anaphase telophaseanaphase telophase
Cytokinesis : cytoplasmic divisionCytokinesis : cytoplasmic division
G1
S
S
G2
M
Animal Cell MitosisAnimal Cell Mitosis
Animation Reference:Animation Reference:
http://www.cellsalive.com/mitosis.htmhttp://www.cellsalive.com/mitosis.htm
Interphase
Prophase
Metaphase
Anaphase
Telophase
Onion Root Tips - MitosisOnion Root Tips - Mitosis
Reference:http://www.biology.arizona.edu/cell_bio/activities/cell_cycle/cell_cycle.html
MeiosisMeiosis A special cell division, for the A special cell division, for the
formation of sex cells.formation of sex cells. For the formation of egg – oogenesis.For the formation of egg – oogenesis. For the formation of sperm – For the formation of sperm –
spermatogenesis.spermatogenesis. Resulting cells only have ½ no. of Resulting cells only have ½ no. of
chromosomes and ½ amount of DNAchromosomes and ½ amount of DNA
Animal Cell MeiosisAnimal Cell Meiosis
Animation Reference:
http://www.people.virginia.edu/~rjh9u/meioanim.html
Comparison of Comparison of Mitosis and MeiosisMitosis and Meiosis
Animation Reference:Animation Reference:http://biology.clc.uc.edu/courses/bio104/meiomito.htmhttp://biology.clc.uc.edu/courses/bio104/meiomito.htm
Differences between Mitosis and MeiosisDifferences between Mitosis and Meiosis
MitosisMitosis MeiosisMeiosis
No. of cell division No. of cell division 11 22
No. of daughter No. of daughter cellscells
22 44
Amount of DNAAmount of DNA same same halfhalf
Amount of Amount of chromosomechromosome
samesame halfhalf
Crossing over, Crossing over, synapsissynapsis