E1 assesment

Question 1

What is the nucleus?

Answer 1

Controls the activity of the cell

Question 2

What is the mitochondria?

Answer 2

oval shaped, have double membrane- site of aerobic respiration- produces ATP (energy source)

Question 3

Endoplasmic reticulum?

Answer 3

system of membranes enclosing a fluid filled space- surface is covered in ribosomes, folds and processes proteins made at the ribosomes.

Question 4

WHATS THE GOLGI APPARATUS?

Answer 4

fluid filled, membrane bound flattened sacs- processes and packages new lipids& proteins. Also make lysosomes.

Question 5

Lysosomes?

Answer 5

Contain digestive enzymes called lysozymes, used to digest invading cells or to break down worn out components of the cell.

Question 6

Formula for magnification?

Answer 6

AIM- actual size= image size divided by real size (height of the object) MAGNIFICATION= size of image divided by size of real object

Question 7

What is magnification?

Answer 7

How large and image is compared to real life.

Question 8

What is resolution?

Answer 8

Amount of information that can be seen in the image.

Question 9

How does the transmission electron microscope work?

Answer 9

A beam of electrons passes through the specimen and its dispersed by the structures there.

Question 10

Limitations for the transmission electron microscope?

Answer 10

have to view it in a vaccum so cant look at living organisms in it

Question 11

How does the scanning electron microscope?

Answer 11

Specimen coated in a thin layer of metal and a beam of electrons bounces off the surface onto a photographic plate- allows images to be seen in 3D form.

Question 12

Limitations to the scanning electron microscope?

Answer 12

Lower resolution images compared to TFMs

Question 13

Differences between TEM and SEM microscopes?

Answer 13

TFMs specimen has to be thin and its in 2D but SFMs have to be thick specimens and its in 3D

Question 14

4 stages of mitosis

Answer 14

1. prophase
2. metaphase
3. anaphase
4. telophase

Question 15

What happens in prophase?

Answer 15

the chromosomes condense and shorten in size, tiny bundles of proteins (centrioles) start moving to opposite poles of the cell, forming a network of protein fibres called the spindle.
The nuclear envelope (membrane around the nucleus) breaks down and chromosomes lie free in the cytoplasm.

Question 16

What happens in metaphase?

Answer 16

the chromosomes ( each with two chromatids) line up in the middle of the cell attaching to the spindle by the centromere.

Question 17

What happens in anaphase?

Answer 17

In anaphase, the centromeres divide separating the sister chromatids , the spindles then contract pulling the chromatids to opposite poles of the spindle, centromere first. Makes chromatids look like a V-shape.

Question 18

What happens in telophase?

Answer 18

The chromatids reach opposite poles on the spindle. They then uncoil = long and thin again
Now called chromosomes again
Nuclear envelope forms around each of the chromosomes, so there are now 2 nuclei.
Cytoplasm divide (cytokinesis)= 2 daughter cells identical