Prokaryaotic And Eukarayotic Cells Flashcards Preview

ALexvel Biology > Prokaryaotic And Eukarayotic Cells > Flashcards

Flashcards in Prokaryaotic And Eukarayotic Cells Deck (21):

Describe the function of
- slime capsule
- pili

Plasmid- small circle of DNA
Slime capsule- slimy layer in the surface for protection and to prevent dehydration
Pili- thin protein tubes, allow bacteria to adhere to surfaces
Flagellum- hollow cylindrical structure rotates to move the cell making it motile


Describe centrioles

-Every animal cell has one pair
-Hollow cylinders made up of protein microtubules
-involved in the formation of the spindle (spindle fibres) during cell division


Describe mitochondrion

-Composed of double membrane outer layer surrounding the matrix
-involved in aerobic respiration


Describe the nucleus

-Enclosed by a double membrane nuclear envelope
- contains chromosomes and a nucleolus


Describe the Nucleolus

- A dark area of the nucleus where ribosomes are made


Describe the rER (Rough endoplasmic reticulum)

-A system of membrane bound organelle with ribosomes attached to the outer surface
-Protein is transported through these tubes to other part of the cell


Describe ribosomes

- made of RNA and protein
- found in the cytoplasm or attached to the rER
-site of protein synthesis (translation)


Describe the cell surface membrane

- Phospholipid bilayer forming a partially permeable barrier
-controls what leaves and enters the cell


Describe the sER (smooth endoplasmic reticulum)

- A system of membrane bound tubes without ribosomes
-makes lipids and steroids


Describe Golgi apparatus

-stacks of flattened, membrane bound sacs formed by fusion of vesicles from rER
- modifies proteins and packages them into vesicles for transport


Describe lysosomes

- Spherical membrane bound sacs containing digestive enzymes
- involved with the breakdown of unwanted or damaged organelles within the cell


Describe the process ,including all organelles and molecules, involved in protein production and trafficking
(9 points)

1. Transcription of DNA to mRNA
2. mRNA leaves nucleus
3. Protein made on ribosomes enter rough ER
4. Protein moves through the ER assuming 3D shape en route
5. Vesicles pinched off rER contain protein
6. Vesicles from rER fuse to form the flattens sacs of the Golgi apparatus
7. Proteins are modified within Golgi apparatus
8. Vesicles pinched off Golgi apparatus contain modified protein
9. Vesicles fuses with cell surface membrane releasing protein


Describe the function of lipid droplets in an ovum

An energy store for developing embryo


Describe the function of lysosomes (or cortical granules)

Release enzymes by exocytosis to thicken the zona pellucida once one sperm cell has fused with the egg cell-
Prevents polyspermy


Describe the function of zona pellucida

Thickens after one sperm cell has fused with egg


Describe the function of follicle cells in the ovum

Release chemicals which stimulate the start of the acrosome reaction


Describe the haploid nucleus in the ovum

Restored the diploid number at fertilisation


Describe the haploid nucleus in a sperm cell

Restores the diploid number at fertilisation


Describe the function of the acrosome in a sperm cell

Modified lysosomes containing digestive enzymes released in the acrosome reaction to digest route through layer of follicle cells and zona pellucida


Describe the function of mitochondria in sperm cells

Produces energy in the form of ATP to power flagellum to propel sperm towards egg


Describe the importance of meiosis in the formation of human gametes

It is a form of cell division that
1. Halves the chromosome number
2. So that at fertilisation the full number of chromosomes if restored
3. Allows genetic variation (in gametes)
4. Through independent assortment
5. Through crossing over genes