Basic component of a cell and it's organelles WK2

Question 1

Describe the cell. i.e. its function and importance

Answer 1

-responsible for all structural/ functional properties of living orgs
-important to know; workings of human body, mechanisms of disease, rationale of therapy

Question 2

Describe some cell shapes (following answer, look at example images)

Answer 2

Squamous-thin and flat
Cuboidal- cube shaped
Columnar- taller than wide
Fusiform- thick in middle, tapered toward ends

Question 3

Describe the limit on cell size

Answer 3

overly large cells can’t support self-may rupture
-Increase diameter, volume increase more than SA
- Volume proportional to cube of diameter
-SA proportional to square of diameter

Question 4

Name and describe three basic components of a cell

Answer 4

Plasma cell membrane
-Surrounds cell
-Controls traffic of molecules in/out

Cytoplasm
-Organelles, cytoskeleton, inclusion (stored or foreign particles), cytosol (intracellular fluid, ICF)

Extracellular fluid (ECF)
-Fluid outside cells
-Includes tissue

Question 5

Provide description and structure of cytoplasm (label on diagram)

Answer 5

-Cytosol (intracellular fluid)
-Higher K+ conc lower Na+ conc
-Higher conc of suspended proteins (e.g. Enzymes)

-Contains; Carbohydrates and lipids (provide energy) and a.acids (manufacture proteins)

Question 6

Provide function, location and description of nucleus (be able to label)

Answer 6

-DNA replication, transcription into mRNA, and ribosomal RNA synthesis occur in nucleus

-Largest organelle (5μm diameter)
-Contains cellular DNA and nucleolus

-In cell

Question 7

Provide function and description of nuclear envelope

Answer 7

-double membrane around nucleus
-perforated by nuclear pores formed by protein rings

-regulate molecular traffic through envelope, hold membrane layers together

Question 8

Provide function and description of nuclear lamina

Answer 8

-Supports nuclear envelope
-points of attachment to chromatin
-Helps regulate cell life cycle

-Web of protein filaments

Question 9

Provide description of chromatin

Answer 9

Thread-like composed of DNA and protein

Question 10

Provide function and description of nucleoli

Answer 10

-Protein synthesis

-Masses where ribosome are produced

Question 11

Provide function and description of mitochondria

Answer 11

-specialised for synthesising ATP
-energy extracted from organic molecules, transferred to ATP

-Surrounded by double membrane
-Inner membrane folds=cristae (line in shape)
-Spaces between cristae= matrix
-Matrix contains ribosomes, enzymes for ATP synthesis, small circular mtDNA

Question 12

Provide function and description of rough ER

Answer 12

-Produces phospholipids+proteins of plasma membrane
-Synthesises proteins packaged in organelles or secreted from cell

-Parallel, flattened sacs covered w/ ribosomes
-cisternae thought to be continuous

Question 13

Provide function and description of smooth ER

Answer 13

-Synthesises steroids+other lipids
-Detoxifies alcohol and other drugs
-Calcium storage

-Lack ribosomes
-Cisternae tubular and branching

Question 14

Provide function and description of ribosome

Answer 14

-Read coded genetic messages (mRNA) and assembles a.acids into proteins specified by code
-Membrane bound or free

-Small granules of protein and RNA
-Found in nucleoli, cytosol, outer surfaces of rough ER, and nuclear envelope

Question 15

Provide function and description of lysozymes

Answer 15

-Autophagy-digestion of cell’s surplus organelles
-Autolysis- ‘cell suicide’-digestion of a surplus cell by itself

-Package of enzymes bound by membrane
-Generally round, but variable in shape

Question 16

Provide function, description and location of Golgi apparatus/complex

Answer 16

-Transport vesicles, containing newly synthesised proteins (NSP), from rough ER
-Modifies, packages, sorts NSP into vesicles that become;
.Lysosomes, secretory vesicles, or migrate to plasma membrane and fuse

-Series of flattened sacs (cisternae)

-Cytoplasm-adjacent to rough ER

Question 17

Provide function, description and location of peroxisome

Answer 17

-use molecular O2 to oxidise organic molecules
-Reactions produce hydrogen peroxide
-excess broken down by catalase =H2O and O2
-Break down fatty acids into acetyl groups for use in ATP synthesis

-Contain different enzymes and are produced by ER

-cytoplasm

Question 18

Describe the differing structures of DNA and RNA

Answer 18

DNA
-A,C,G,T
-Double strand nucleotides
-Genetic material in nucleus of cell

RNA
-A,C,G,U
-Single strand of nucleotides
-Cytoplasm (outside nucleus)
- Carries out instructions for protein synthesis

Question 19

Describe mtDNA

Answer 19

-Inherited from mother
-Mutates more rapidly than nuclear DNA
-cause hereditary diseases affecting tissues with high energy demands

Question 20

Provide description and structure of ER

Answer 20

-System of channels (cisternae) enclosed by membrane
-Rough and smooth ER functionally different, parts of same network

Question 21

Provide structure and function of proteasomes

Answer 21

-Hollow, cylindrical organelles
-dispose of surplus proteins
-contain enzymes break down tagged, targeted proteins=short peptides and amino acids

Question 22

Provide structure, description and function of centrioles

Answer 22

-Short cylindrical assembly of microtubules
-Arranged in 9x3 microtubules each

-important role in cell division
-Form basal bodies of cilia+flagella
-Each body is centriole originated in centriolar organising centre, then migrated to membrane

Question 23

Describe inclusions and the two kinds

Answer 23

-Never enclosed in a unit membrane
-Not essential for cell survival

Stored cellular products
-Glycogen granules, pigments, fat droplets

Foreign bodies
Viruses, intracellular bacteria, dust particles, debris

Question 24

Provide description and movement of flagella

Answer 24

-Tail of a sperm
-Whip-like structure, axoneme identical to that of cilia
-Much longer than cilium
-Reinforced by coarse fibers that support the tail

-Movement undulating, snake-like, corkscrew
-No power stroke or recovery strokes

Question 25

Provide description and function of pseudopods

Answer 25

-Continually changing extensions of cell
-Vary in shape/size

-for cellular locomotion, capturing foreign particles