Download Semester 1 extra practice worksheet-model answers

SEMESTER 1 EXTRA PRACTICE WORKSHEET
MODEL ANSWERS
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37.
A.
centrioles
B.
Nucleus
C.
Lysosome
D.
Nucleolus
E.
Golgi complex
F.
Rough endoplasmic reticulum
G.
Ribosomes
H.
Cytoplasm
I.
Cell membrane
J.
Mitochondria
A plant cell would have:
a) A large central vacuole
b) A cell wall
c) Chloroplasts
38. Cell membrane main constituents: phospholipids, proteins, carbohydrates, cholesterol
39.
1) Passive transport
2) Concentration gradients
3) Facilitated diffusion
4) Simple diffusion
5) Active transport
6) Sodium potassium pump
7) Endocytosis
8) Ion channels
40.
a) Both
b) F
c) A
d) A
e) F
41. Osmosis is specific to the movement of water molecules only and requires the presence of a
semi-permeable membrane. Diffusion is the movement of any substance from an area of high
concentration to an area of lower concentration.
42. Facilitated diffusion and active transport both involve transport proteins. Facilitated diffusion
occurs without using energy and down the concentration gradient (from high to low
concentration).
43. Cell cycle is made up of 5 stages:
 Gap 1 (G1): the cell carries out its normal functions and grows in size. A checkpoint must
be passed before moving on to the next stage. Cell size, growth, functions and nutritional
status are evaluated in the checkpoint.
2
 Synthesis (S): DNA is replicated (copied)
 Gap 2 (G2): the cell carries out its normal functions and grows further in size. A critical
checkpoint must be passed; where DNA copying is checked for errors.
The first three stages are collectively called the interphase.
 Mitosis: 4 STAGES
a) Prophase:
 the chromosomes condense and become visible
 The nuclear membrane disintegrates
 The spindle starts to form
b) Metaphase:
 Chromosomes align at the equator of the cell
 Spindle fibers stretch and attach to the chromosomes at the centromeres
c) Anaphase:
 Spindle fibers shorten pulling chromatids to opposite poles of the cell
 Centromeres divide
d) Telophase: (opposite of prophase)
 Chromosomes start to uncoil
 New nuclear membranes start to form
 The spindle breaks down (becomes part of the new cells’ cytoskeleton)
END OF MITOSIS
 Cytokinesis: COMPLETES THE CELL CYCLE
 In animal cells: protein filaments form a belt which pinches the cell into 2.
 In plant cells: the Golgi complex forms vesicles which align to form a cell plate. The
cell plate then forms the new cell walls for the daughter cells.
GOOD LUCK!
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