Topic 2 Flashcards Preview

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Flashcards in Topic 2 Deck (21):
1

Microscopes

Have the ability to increase the resolution and magnification of cells

2

Magnification

Visually enlarging an object to make it seem larger in appearance, although it doesn't physically become larger

3

Resolution (resolving power)

The minimum distance apart that two points must be in order for them to be seen as two discrete points

4

1mm

1000 um (micrometer)

5

1um

1000 nm (nanometers)

6

Optical (Light) microscope

Specimens are illuminated by visible or ultraviolet light, or laser light
Light focused using lenses
lower levels of resolution and magnification
coloured image
living cells

7

Electron microscope

specimen illuminated by electron beam that is focused by electromagnets on the specimen
focused using electromagnets
higher levels of resolution and magnification
black and white image (unless false-coloured)
Dead cells- specimens already coated with an ultra-thin layer of metal and placed in a vacuum

8

Photomicroscopy

performed by hooking up a regular camera to a microscope, thereby enabling the user to take photographs at reasonably high magnification

9

Electron micrograph

micrograph prepare using electron microscope- higher magnification and resolution

10

Light micrograph

Micrograph prepared using a light microscope, a process referred to as photomicroscopy

11

Scanning electron microscope

Electron beam interacts with the surface of a bulk specimen
Reveals texture and surface details and makes a 3D shape
Used to examine the 3D surface of cells and tissues

12

Transmission electron microscope

Uses a focused electron beam that passes through an ultra-thin slice of a cell, revealing very fine detail.
Higher resolution than SEM
used for studying cell infrastructure

13

Evidence for endosymbiosis

Mitochondria and chloroplasts similar to prokaryotic cells
- contain their own DNA, which is circular, unlike linear DNA molecules in chromosomes in nucleus
-contain free ribosomes which are smaller than those in eukaryotes
- made up of double membrane

14

Evolution of mitochondria

Mitochondria evolved from a primitive eukaryote engulfing, but not digesting, a prokaryote through endophagocytosis
the prokaryote could perform aerobic respiration- most efficient means of ATP production
beneficial relationship between eukaryote and prokaryote and they had an advantage over other cells and lived on as they produced offspring
overtime they lost the ability to live independently and thus the evolution of mitochondrion, the site of aerobic respiration

15

Evolution of chloroplast

after mitochondria was engulfed by eukaryotes
eukaryote engulfed a prokaryote with the ability to carry out photosynthesis
the eukaryote and photosynthetic prokaryote evolved together to become modern day plants

16

Organic molecules

Living organisms are almost exclusively built of organic molecules and these molecules are essential in allowing them to function
Major groups- carbohydrates, proteins, lipids, nucleic acids
Composed of carbon atoms, arranged as chains or rings, and bonded to other atoms, mainly hydrogen, oxygen and sometimes, N,P and S

17

Inorganic molecules

Small molecules that do not contain all of C, O and H
O, C02, H20 and salts and mineral ions
essential to the survival of all living organisms

18

Carbohydrates

Monosaccharide (glucose)
e.g. starch (energy storage in plant cells)

19

Proteins

Amino acids
e.g. amylase (salival enzyme)

20

Lipids

Fatty acid and Glycerol
e.g. Phospholipids

21

Nucleic Acids

Nucleotides
e.g. DNA, rRNA