Cells

Question 1

Which organelles in eukaryotic cells are membrane-bound?

Answer 1

Lysosomes, RER, SER, Golgi apparatus, Mitochondria.

Question 2

What is the difference between free ribosomes and the ribosomes on the RER?

Answer 2

Free ribosomes synthesize proteins that stay within the cell cytoplasm, RER ribosomes create proteins that are excreted or attached to the cell membrane.

Question 3

What are the prokaryote-specific features?

Answer 3

• Mesosomes
• Cell wall - made of glycoprotein
• Flagellum
• Pili
• Slimy capsule
• Plasmids
• No membrane-bound organelles in the cytoplasm

Question 4

What is the formula for magnification?

Answer 4

Size of image / size of real object

Question 5

Give an example of how similar cells are organised into tissues

Answer 5

Ciliated epithelium: cells covered in cilia, found in the trachea.

Question 6

Give an example of how tissues are organised into organs

Answer 6

The leaf: contains the lower epidermis (stomata allow GE), the spongy mesophyll (allows G circulation), the xylem (carries water to the leaf) and phloem (carries nutrients away from the leaf), the palisade mesophyll (photosynthesis), and the upper epidermis (roofed by a waxy cuticle to reduce water loss).

Question 7

Give an example of an organ system

Answer 7

Respiratory: nose, mouth, larynx, trachea, lungs and diaphragm.

Question 8

What happens in mitosis and what’s it used for?

Answer 8

A parent cell divides to produce two genetically identical daughter cells. Mitosis is necessary for asexual reproduction and for repairing damaged tissue.

Question 9

What are the three parts of interphase and what happens in them?

Answer 9

G1 = cells grows, new organelles and proteins made.
Synthesis = cell replicates its DNA
G2 = cells keeps growing, proteins for cell division are made

Question 10

What happens in prophase and metaphase?

Answer 10

Prophase: chroms. condense (become short & fat), centrioles move to opposite cell ends, forming protein fibres (a spindle) between them, nucleur env. breaks down and chroms. lie free in the cytop.
Metaphase: chroms. line up in the centre of the cell, attached to the spindle by their centromeres.

Question 11

What happens in anaphase and telophase?

Answer 11

Anaphase: centromeres divide and separate the pairs of sister chromatids, spindles contract and pull them to opposite poles of the spindle, centromere first (look v-shaped).
Telophase: chromatids reach the opposite poles, uncoil and become chroms. again, nuclear envelope forms around the two groups of chroms. creating two nuclei, cytokineses occurs, two daughter cells produced.

Question 12

How is the mitotic index calculated and what does it indicate?

Answer 12

no. of cells with visible chromosomes / total no. of cells observed
Indicates the rate of tissue growth.