Cell City
Which can be unicellular: eukaryotes, prokaryotes, or both?
Both
Describe the role of protein channels
Permanent channels that control the movement of specific molecules into and out of the cell
What is the active site of an enzyme.
The region of the enzyme where the substrate binds and the reaction occurs.
Put these three processes of urine formation in the correct order:
secretion
glomerular filtration
selective reabsorption.
Glomerular filtration → selective reabsorption → secretion
Where in the cell does glycolysis occur?
Cytoplasm
It modifies, sorts and packages proteins and lipids into vesicles for transport within or out of the cell
Draw a phospholipid (on the board) and explain the two main sections.
Hydrophilic phosphate head: polar and attracted to water.
Hydrophobic fatty acid tails: non-polar and repel/avoid water.
Which enzyme breaks down proteins during digestion?
Protease
Name three substances normally found in the filtrate after glomerular filtration
Water, glucose, amino acids, ions/salts, urea.
List the three main stages of aerobic respiration in order
1. Glycolysis
2. Krebs Cycle
3. Electron Transport Chain
What is the key difference in function between the rough ER and smooth ER?
Rough ER has ribosomes and is involved in protein production/processing, while smooth ER produces lipids and has no ribosomes.
Explain the difference between simple diffusion and facilitated diffusion
Both move substances down the concentration gradient without ATP, but facilitated diffusion requires membrane proteins/channels.
An enzyme is at its optimum temperature and pH. Substrate concentration keeps increasing, but the reaction rate eventually stops increasing. Explain why.
All active sites become occupied. Because the enzymes are saturated, adding more substrate cannot increase the rate.
What is the difference between the glomerulus and Bowman's capsule
The glomerulus is a network of capillaries where blood is filtered, while Bowman’s capsule surrounds the glomerulus and collects the filtrate.
What happens when the guard cells swell?
The stomata open, allowing greater gas exchange.
Explain how mitosis and differentiation allow stem cells to form tissues.
Stem cells divide by mitosis to produce more cells. Some of these cells then differentiate into specialised cells with particular structures and functions. Groups of similar specialised cells form tissues.
A substance moves from an area of low concentration to high concentration across the membrane. What type of transport is occurring and what does it require?
Active transport. It requires ATP and a transport protein/pump.
An enzyme’s activity increases as temperature rises, then rapidly decreases above 40°C. Explain why.
Higher temperature initially increases collisions, but excessive heat changes the enzyme’s shape/denatures it, altering the active site.
Compare glomerular filtration and selective reabsorption.
Glomerular filtration: small substances move from the blood into Bowman’s capsule.
Selective reabsorption: useful substances move from the filtrate back into the blood.
What is the net ATP output of aerobic respiration?
36–38 ATP
A cell suddenly has a build-up of damaged organelles and cellular waste. Which organelle is most likely not functioning properly? Explain your answer.
Lysosomes. They contain digestive enzymes that break down cellular waste, damaged organelles and other unwanted materials. If lysosomes stopped functioning, these materials would accumulate in the cell.
An animal cell is placed in a solution with a lower solute concentration than inside the cell. Name the process occurring, predict what will happen to the cell, and explain why.
Osmosis. Water moves into the cell across the selectively permeable membrane, from the solution with lower solute concentration to the area of higher solute concentration. The cell will swell and may burst (lyse).
A molecule has a similar shape to an enzyme’s substrate and competes for the active site. What is this molecule called, and how does it affect enzyme activity?
A competitive inhibitor. It occupies the active site and reduces the number of substrate molecules that can bind, decreasing reaction rate.
A person becomes dehydrated and produces a smaller volume of more concentrated urine. Explain which part of the nephron is mainly responsible for this and how.
The collecting duct reabsorbs more water from the filtrate back into the blood. This leaves less water in the filtrate, producing a smaller volume of more concentrated urine.
What is the powerhouse of the cell
The Mitochondria