Chapter 2 Definitions

Question 1

Cell

Answer 1

the smallest structural and functional unit of an organism, typically microscopic and consisting of cytoplasm and a nucleus enclosed in a membrane.

Question 2

Nucleic Acids

Answer 2

a complex organic substance present in living cells, especially DNA or RNA, whose molecules consist of many nucleotides linked in a long chain.

Question 3

RNA

Answer 3

RNA transcribed inside the nucleus is exported to the cytoplasm through nuclear pores. They act as a gateway allowing only specific materials in and out of the nuclear envelope

Question 4

Microscopy

Answer 4

A technique used for producing visible images of objects, biological or otherwise, that are too small to be seen by the human eye.

Question 5

Illumination

Answer 5

the act of illuminating or the state of being illuminated

Question 6

Magnification

Answer 6

how much bigger you can make an object appear dependent upon the lens system

Question 7

Resolution

Answer 7

measure of the clarity of the image or ability to differentiate between two dots dependent upon the wavelength of light used ==> Blue light has a shorter wavelength than red (400 vs 600 nm) so it will provide better resolution==> x-rays have an even shorter wavelength and can provide even greater resolution

Question 8

View

Answer 8

inside or outside of the cell, type of light

Question 9

Plasma Membrane

Answer 9

a phospholipid bilayer with proteins that separates the cell from the surrounding environment and functions as a selective barrier for the import and export of materials

Question 10

Bilayer

Answer 10

A double layer of phospholipids in which the tails face inwards and are hydrophobic and the phosphate groups face outwards and are hydrophilic. This allows for the membrane to be selectively permeable.

Question 11

Hydrophobic

Answer 11

‘repels water’

Question 12

Hydrophilic

Answer 12

‘likes water’

Question 13

Gene

Answer 13

A unit containing the code for a protein molecules or one of its parts, or functioning RNA molecules such as tRNA and rRNA

Question 14

Cytoplasm

Answer 14

All parts of the cell that surround the central nuclear or nucleoid region

Question 15

Organelle

Answer 15

The nucleus and other specialized internal structures and compartments of eukaryotic cells

Question 16

Cytoskeleton

Answer 16

The interconnected system of protein fibres and tubes that extends throughout the cytoplasm of a eukaryotic cell

Question 17

Prokaryote

Answer 17

Organism in which DNA is suspended in the cell interior without separation from other cellular components by a discrete membrane

Question 18

Eukaryote

Answer 18

Organisms in which DNA is enclosed in a nucleus

Question 19

Nucleus

Answer 19

The central region of eukaryotic cells, separated by membranes from the surrounding cytoplasm, where DNA replication and messenger RNA transcription occur

Question 20

Nucleoid

Answer 20

The central region of a prokaryotic cell with no boundary membrane separating it from the cytoplasm, where DNA replication and RNA transcription occur

Question 21

Messenger RNA (mRNA)

Answer 21

A RNA molecule that serves as a template for protein synthesis

Question 22

Ribosomal RNA (rRNA)

Answer 22

The RNA component of ribosomes

Question 23

Ribosomes

Answer 23

ribonucleotide particle that carries out protein synthesis by translating mRNA into chains of amino acids

Question 24

ATP

Answer 24

The primary agent that couples exergonic and endergonic reactions

Question 25

Flagellum

Answer 25

A thread-like protein fibre which extend from the surface of the cell and are used in bacteria and archeans to move through liquids and across wet surfaces.

Question 26

Pilus

Answer 26

Hair-like shafts of protein extending from the cell walls of some bacteria and archea. It’s main function is to attach the cell to the surfaces of other cells. There is a special type of ‘sex’ pilus which attaches one bacterium to another during mating.

Question 27

What makes something alive (7)

Answer 27

1. Cells and Organization2. Energy Use and Metabolism3. Response to the Environment4. Homeostasis5. Growth and Development6. Reproduction7. Biological Evolution

Question 28

Describe cell theory (3)

Answer 28

1. All organisms are made up of one or more cells2. The cell is the basic unit of all living organisms3. Cells cannot be created but come from existing cells

Question 29

4 basic structures in all living cells

Answer 29

==> DNA-containing region==> Cytoplasm==> Ribosomes==> Plasma Membrane

Question 30

Typical Light Microscope

Answer 30

==> Very versatile==> Uses light to illuminate the specimen==> Generally uses contrast, pigments, or dyes==> Types include phase contrast and differential interference contrast==> Fluorescent microscopy is also used (fluorescent and confocal laser scanning)

Question 31

Typical Electron Microscope

Answer 31

==> Uses electrons to illuminate the specimen==> 2 types are TEM and SEM

Question 32

Why are cells very small?

Answer 32

==> If cells increase in diameter they also increase in volume==> However volume increases more rapidly than surface area==> Thus, exchange of substances between the cell and its environment can become limiting

Question 33

Function of Plasma Membrane

Answer 33

Is made up of a phospholipid bilayer and determines what comes and goes from the cell.