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