Unit 2: Cells

Question 1

Cell membrane composition?

Answer 1

Phospholipid bilayer, proteins and sensory / regulatory molecules

Bilayer is made up on phospholipids, glycolipids, glycoproteins, cholesterol, membrane proteins

fluid-mosaic due to non-rigid almost fluid-like structure

Question 2

Cytoplasm

Answer 2

All material contained in cell

made of cytosol and 80% water

suspends organelles in place and acts as a medium for molecule transport and maintains cell structure

Question 3

Nucleus and Nucleolus

Answer 3

Command center containing DNA condensed as chromatin

Surrounded by nuclear envelop with nuclear pores to allow entry and exit

Contains nucleolus which is responsible for RNA production

Question 4

Endoplasmic reticulum

Answer 4

Attached to nucleus, contains cisternae folded tunnels and acts as a means for molecule travel

Rough er: studded with ribosomes, produces proteins
Smooth er: produces lipids and steroids, scarce compared to RER

Question 5

Ribosomes

Answer 5

Produces proteins, composed of two subunits of rRNA

free in cytoplasm or on RER

site of protein synthesis

groups of ribosomes = polysomes

Question 6

Golgi Apparatus and vesicles

Answer 6

Packaging plant of cell, taking molecules from ER and modifying and packing for distribution

Packs molecules into vesicles

Has cisternae, similar composition as membrane

Vesicles are small membrane bound sacks made of phospholipid bilayer

vacuoles, lysosomes, transport and secretory vesicles

Question 7

Types of vesicles:

Answer 7

Vacuoles: store water and other molecules

Lysosomes: break down molecules, contains digestive enzymes

Transport vesicles: specializes in movement inside cell

Secretory vesicles: specializes in movement outside cell

Question 8

Mitochondira

Answer 8

Powerhouse of cell, site of cellular respiration, has different DNA from rest of cell

Question 9

Endocytosis types

Answer 9

Endocytosis: cell membrane forms a vesicle around the molecules it wants to take in and then merges it

phagocytosis: large materials (other cells) are taken in through vesicle, seen at low magnification

pinocytosis: large molecules are taken in through vesicle, seen at higher magnification

receptor-mediated endocytosis: receptors on membrane trigger from specific molecules to form vesicles

Question 10

Exocytosis

Answer 10

Molecules are removed from cells by the merging of a vesicle carrier

secreting cells (ex hormones) perform lots of exocytosis

Question 11

Cellular respiration

Answer 11

Occurs at the mitochondria

O2 + C6H12O6 -> H2O + CO2 + ATP

Glycolysis: at cytosol
Krebs Cycle: matrix
Oxidative Phosphorylation: between matrix and intermembrane space

Question 12

Glycolysis

Answer 12

Anaerobic, converts glucose to pyruvate and 2 ATP and 2 NADH

Question 13

Krebs Cycle

Answer 13

Aerobic process where pyruvate from glycolysis is converted into Acetyl-CoA, which enters the Krebs cycle.

Acetyl-CoA is broken down, releasing carbon dioxide and transferring energy to NADH and FADH2.

2 ATP + CO2 + NADH + FADH2

Question 14

Oxidative Phosphorylation

Answer 14

NADH and FADH2 produced in previous stages donate electrons to the ETC. As electrons move through the chain, protons (H+) are pumped across the membrane, creating a proton gradient. Oxygen is the final electron acceptor, combining with electrons and protons to form water.
ATP Production: The proton gradient drives ATP synthase to produce ATP. This stage produces the most ATP.

+34 ATP molecules

Question 15

Negative / Positive Feedback

Answer 15

Feedback loop signals to either produce more (positive) or stop producing (negative)

Baby contractions = negative feedback