A2.2

Question 1

the cell theory

Answer 1

1. All cells come from pre-existing cells.
2. All organisms are made out of one or more cells.
3. Cells are the smallest unit of life.

Question 2

Light microscopes

Answer 2

Allows us to see large structure in the cells.
Stains can be used to highlight certain strucutres (Methylene blue stains).

Question 3

Electron microscopes

Answer 3

Made it possible to study the ultrastructure of the cells (the ogranelles).

Question 4

Florescence microscope

Answer 4

allows you to see a certain part of the cells, a dye will highlight certain structures (DNA, proteins and microtubules).
living cells.

Question 5

Immunofluorescence microscopy

Answer 5

(Fluroscence markers bind to specific chemicals).
Allows us to track chemicals in the cell

Question 6

Freeze fracture electron microscopy

Answer 6

to study different organelles.
high resolution.
unique view of membrane strcutre, macromolecular strucutre.

Question 7

Cryogenic electron microscopy

Answer 7

allows us to study the structure of proteins.
high resolution image

Question 8

Functions of life

Answer 8

Growth
Metabolism (chemical reactions, energy converted from one form to the other)

Reproduction (heridetary molecules passed to the offspring)

Responses (adaption to the environment)

Homeostasis (organisms maintains a constant internal environment (temp, ph).

needs nutrition
(sources of enegry and building blocks)

excretion (unsusable or toxic compounds need to be disposed).

Question 9

Structures in cells common to all organisms

Answer 9

1. Plasma membrane
   - outer boundary of the cell. Decided what goes in and out (selectively permeable)
2. Cytoplasm
   - Cytosol + organelles + cytoskeleton = cytoplasm. Cytosol is the liquid inside the membrane. Made out of water and dissolved solutes, sugar or amino acids, needed to carry out metabolic processes. Enzymes carrying out reactions (met.) provides energy to build molecules (pro.).
3. DNA
   - contains genes, which holds information for a funciton. Genes produce proteins (enzymes/structural proteins).

Question 10

Prokaryotic cells

Answer 10

Do not have a nucleus. (Bacteria and Archaea).

Earliest forms of life.

Simple structure, no compartaments inside the cells.

Have a cell wall made out of peptidoglycan (supports and protects the cell).

Organelles: Ribosomes 70S - makes protein.
Nucleoid region contain the singular circular DNA molecule/chromosome.

Question 11

Prokaryotic cells ex.

Answer 11

Bacillus subtillis - hay bacteria. Oval, singular.

Streptococcus epidermidis - skin bacteria.

Question 12

Eukaryotic cells

Answer 12

advanced organelles.

Nucleus - double membrane (nuclear envelope) with nuclear pores. Contain many linear chromosomes. DNA molecules are wrapped around molecules (histones). - NUCLEOSOME
NUCLEOLUS - a region dense in DNA, responsible for creating ribosomes.

Entire DNA loosely wrapped, ready to use, is called chromatin. Before cell division, DNA is tightly packed into chromosomes.

80s Ribosomes

Compartamelised

Mitochondria
- inner membrane folded to increase area. Carried out aerobic cell respiration.

Question 13

Atypical cells - Red blood cells

Answer 13

transports oxygen - no nucleus.

Question 14

Phloem sieve tube

Answer 14

tube-like cell transporting sugar in plants. Almost no organelles. Companion cells keep them alive through large pores between the cells.

Question 15

Skeletal muscle

Answer 15

several nuclei due to fused cells (joined or blended).

Question 16

Aseptate fungal hyphae

Answer 16

roots of certain fungi. Long multinuclear cells.