cell structure and function

Question 1

⬡ Physical separation between the inner cell
and external environments.
⬡ Site of nutrient and waste exchange.
⬡ Sensation of environmental changes or
communication from other cells.
⬡ Structural connection to neighboring cell

Answer 1

Plasma Membrane Functions

Question 2

• the barrier that surrounds all cells and forms their surface.
• ______are selectively permeable,
  meaning only certain molecules can pass.
• Small nonpolar- , molecules (CO2, O2) are freely
  permeable.
  *Large polar molecules - (glucose, proteins,
  water) are impermeable without a protein
  channel

Answer 2

plasma membrane

Question 3

the main component of plasma membranes.
⬡ Hydrophobic fatty acid tails are insoluble in water.
- Hydrophilic “Head” (Phosphate)
- Hydrophobic “Tails” (Fatty Acids)
⬡ Hydrophilic phosphate heads are soluble in water.

Answer 3

Phospholipid

Question 4

–a double-layer sheet where
the hydrophobic tails congregate in the middle.
⬢ Protein-senable communication, transportation, and adhesion

Answer 4

The phospholipids form a bilayer

Question 5

Water Vapor (H2O)
⬡ Nitrogen (N2)
⬡ Carbon Dioxide (CO2)
⬡ Methane (CH4)
⬡ Ammonia (NH3)

Answer 5

Life began around 4 billion years ago with an
atmosphere that contained..

Question 6

The _________ was an
experiment constructed to replicate
conditions on the early Earth. ⬡ Electrodes simulated lightning. ⬡ The 5L flask was filled with gases
found in the early atmosphere.
⬡ A 500mL flask contains boiling water
to simulate evaporation from the
oceans.
⬢ After two weeks… ⬡ Carbon was converted to sugars,
amino acids, and parts of nucleic acids.

Answer 6

Miller-Urey Apparatus

Question 7

The ______explains the importance of
cells to life:
⬢ All living organisms are made of cells.
⬢ Cells express all characteristics of life
(reproduction, homeostasis, etc)
⬢ All existing cells are derived from other
cells.

Answer 7

CELL THEORY

Question 8

-Prokaryotes- Smaller cells (0.1-0.5μm), No nucleus or organelles, Always single-celled
-Eukaryotes- Larger cells (10-100μm), Nucleus and organelles present, Single or multicellular

Answer 8

TYPES OF CELLS

Question 9

is the passive movement of molecules from areas of greater to lower concentration.
⬡ The concentration gradient is the gradually changing amount of the particle across a distance
 Molecules moving from area of high concentration
to area of low concentration
 No energy is required
 Occurs because molecules constantly move and
collide with each other

Answer 9

Diffusion

Question 10

Osmosis

Answer 10

is the movement of water molecules through protein channels called aquaporins.
⬢ Water molecules move towards areas with more solutes(salts, sugars).

Question 11

• Receptor- Respond to chemical signals, like hormones.
• Carrier- Transport materials across membranes.
• Enzymes- Increase the rate of membrane chemical reactions.
• Anchoring- Attachment to other cells.
• Recognition- Identify the cell as “self” to the
  immune system

Answer 11

Types of Membrane Proteins

Question 12

act as lubricants, adhesives, or part of the cell recognition system

Answer 12

Membrane carbohydrates

Question 13

• are selectively permeable, meaning only certain molecules can pass.
• Small nonpolar- molecules (CO2, O2) are freely permeable.
• Large polar molecules-
  (glucose, proteins, water) are impermeable without a protein channel.

Answer 13

Plasma membranes

Question 14

Solution Tonicity

Answer 14

*Hypertonic-
Higher concentration of
solute outside of cell.
Water moves out of cell.
Cell shrivels.

*Hypotonic-
Lower concentration of
solute outside of cell.
Water moves in to the cell
Cell bursts.

*Isotonic-
Equal concentration of
solute in and out of cell.
Water moves in and out.
No cell change.

Question 15

Protein channels allow the
diffusion of molecules that would
otherwise be impermeable.
Passive: No energy required

Answer 15

Facilitated Diffusion

Question 16

Protein channels move
substances against the
concentration gradient.
Active: requires energy

Answer 16

Active Transport

Question 17

uses membranous sacs to transport large amounts of material at once.

Answer 17

Vesicular transport

Question 18

moves material
out of the cell.

Answer 18

Exocytosis

Question 19

moves material in to the cell.
cell membrane engulfs
the larger molecule and brings it into
the cell
 Two types:
◦ Phagocytosis: cytoplasm surrounds a
molecule and packages it in a food
vacuole
◦ Pinocytosis: cell membrane forms
pockets filled with liquid and pinch off to
form vacuoles in a cell

Answer 19

Endocytosis

Question 20

a type of endocytosis where white blood cell engulf bacteria or viruses whole

Answer 20

Phagocytosis

Question 21

the fluid found within cells containing nutrients, ion and proteins.

Answer 21

Cytosolis

Question 22

are individual structures that have specific jobs.

Answer 22

Organelles

Question 23

The ________ is a network of protein filaments that give the cell structure and support its shape.

Answer 23

cytoskeleton

Question 24

Fingerlike
extensions that
increase
surface area

Answer 24

Microvilli (cytoskeleton shape)

Question 25

Cylindrical structures that direct chromosomes during mitosis.

Answer 25

Centrioles (cytoskeleton shape)

Question 26

Long, slender extensions of plasma membrane that can move independently.

Answer 26

Cilia (cytoskeleton shape)

Question 27

Very long extensions of plasma membrane that can move independently.

Answer 27

Flagella (cytoskeleton shape)

Question 28

do all the work in a cell, and must be produced and maintained by a series of structures

Answer 28

Proteins

Question 29

Tiny particles made of RNA that build proteins.

Answer 29

Ribosomes

Question 30

Rough Endoplasmic Reticulum (ER)

Answer 30

Network of membranes covered in ribosomes. “Protein factory."

Question 31

Membranes with no ribosomes that build lipids and carbohydrates

Answer 31

Smooth Endoplasmic Reticulum (ER)

Question 32

Flattened discs of membrane that package proteins in vesicles.

Answer 32

Golgi

Question 33

are temporary storage organelles made of a phospholipid bilayer

Answer 33

Vesicles

Question 34

Contain material to be released outside the cell via exocytosis.

Answer 34

Secretory Vesicles

Question 35

Digestive enzymes that break down worn cell parts, bacteria, or viruses.

Answer 35

Lysosomes

Question 36

- Smaller than lysosomes Digest fatty acids and amino acids. - release a toxic, reactive waste product called hydrogen peroxide (H2O2) . ⬡ Must be neutralized by an enzyme called catalase before it damages the cell.

Answer 36

Perioxisomes

Question 37

the process of cellular respiration to extract the energy in sugars to release ATP, releasing carbon dioxide and water as waste products.

Answer 37

Mitochondria

Question 38

Spread throughout the nucleus.

Answer 38

Chromatin

Question 39

Condensed and tightly coiled.

Answer 39

Chromosomes

Question 40

The ________ separates the DNA from the rest of the cell.

Answer 40

nuclear envelope

Question 41

______ enable the movement of material through the nucleus

Answer 41

Nuclear pores

Question 42

The _______ assembles ribosomes.

Answer 42

nucleolus

Question 43

DNA helicase

Answer 43

the DNA double-helix has to be unwound with an enzyme

Question 44

is the process of copying part of a DNA molecule to a smaller RNA molecule with an enzyme called RNA polymerase. ⬢ The new mRNA molecule can pass through a nuclear pore to the rough ER.

Answer 44

Transcription

Question 45

is single-stranded and uses uracil (U) in place of thymine (T), following this pattern: ⬡ A→ U ⬡ T→ A ⬡ C→ G ⬡ G→ C

Answer 45

mRNA

Question 46

sequences of three bases in mRNA. ⬢ Each codon will translate to a single amino acid in the protein that will be constructed. ⬡ AUG serves as the start codon. ⬡ UAA, UAG, and UGA are stop codons

Answer 46

Codons

Question 47

- is the construction of a protein at a ribosome from the mRNA template. ⬢ mRNA codons are matched up with tRNA anti codons to ensure the correct amino acid is added. - After translation, the protein is packaged in the Golgi for transport

Answer 47

Translation

Question 48

Each codon specifies for only one amino acid. AUU always codes for isoleucine (ILE).

Answer 48

Non Ambiguous

Question 49

The same codon-aminoacid combinations are found in all organisms.

Answer 49

Universal

Question 50

Each amino acid has multiple codons that signal for it. Isoleucine (ILE) s coded by AUU, AUC, and AUA.

Answer 50

Redundant

Question 51

The time spent in between cell divisions. Cells grow and perform their normal tasks during this time.

Answer 51

Interphase

Question 52

The division of the nucleus into two identical copies.

Answer 52

Mitosis

Question 53

The division of the cytosol and organelles.

Answer 53

Cytokinesis

Question 54

The nucleus directs the activities of the cell through the building of proteins

Answer 54

Protein Synthesis

Question 55

Fluid Mosaic Model

Answer 55

Example: -Proteins: forms channels and pumps to move materials across membranes - Carbohydrates: act like identification cards so cells can identify one another

Question 56

 Energy is not required for movement across the membrane to occur  Molecules move from area of high concentration to area of low concentration  Example: Like riding a bike downhill -Two factors determine if passive transport takes place, equilibrium and permeability

Answer 56

Passive Transport

Question 57

when the concentrations on both sides of the membrane are equal

Answer 57

Equilibrium

Question 58

- ability of a molecule to diffuse (move) across a membrane * Impermeable: molecules that cannot pass across a membrane * semi-permeable/selective permeability: Some molecules can pass across the membrane while other molecules cannot

Answer 58

Permeability:

Question 59

 Energy required for molecules to pass across ◦ ATP – the “battery” of the cell ◦ Breaking a bond in ATP releases energy ◦ Can “pump” molecules from low to high concentration (against concentration gradient)

Answer 59

Active transport

Question 60

cytoplasm surrounds a molecule and packages it in a food vacuole

Answer 60

Phagocytosis(endocytosis)

Question 61

cell membrane forms pockets filled with liquid and pinch off to form vacuoles in a cell

Answer 61

Pinocytosis(endocytosis)