Unit 2 Outline Flashcards
mitochondria
transfers energy from organic compounds to ATP
ribosomes
organizes the synthesis of proteins
endoplasmic reticulum
prepares proteins for export (rough ER); synthesizes steroids, regulates calcium levels, breaks down toxic substances (smooth ER)
golgi apparatus
processes and packages substances produced by the cell
microfilaments and microtubules
contribute to the support, movement, and division of cells
cilia and flagella
propel cells through the environment; move materials over the cell surface
nucleus
stores hereditary information in DNA; synthesizes RNA and ribosomes
cell wall*
supports and protects the cell
vacuole*
stores enzymes and waste products
plastid* (chloroplast)
stores food or pigments; one type (chloroplast) transfers energy from light to organic compounds
passive transport
The movement of molecules across a cell membrane without energy input from the cell. The molecules will move from an area of high concentration to an area of low concentration. This can also be referred to as moving down the concentration gradient.
active transport
drives molecules across a membrane from a region of lower concentration to a region of higher concentration or against a concentration gradient. This process requires energy.
diffusion*
The movement of molecules in a fluid or gas from a region of high concentration to an area of low concentration.
- passive
« Examples of Diffusion:
• If you encounter a truck full of pigs, the manure odor will diffuse through the air to your nose.
• Food colouring drops added to a beaker of water will diffuse through the water without energy being added, (agitation or heat)
• Cells continually consume oxygen which means the oxygen concentration is almost always higher outside a cell than it is inside a cell. As a result, oxygen diffuses into a cell without the cell expending any energy.
osmosis*
diffusion of water across a selectively permeable membrane. Is a form of passive transport. Water will always move toward where there are more solutions.
hypotonic*
when concentration of solute molecules outside the cell is lower than inside the cell (in the cytosol) so the solution is hypotonic to the cytosol. (Passive)
- Potato in distilled water
- H2O moves into potato
- Potato will swell and get harder
hypertonic*
when concentration of solute molecules outside the cell is higher than inside the cell, so the solution outside is hypertonic to the cytosol (passive)
- Potato in salt water
- H2O moves out of potato
- Potato will shrivel/get softer
isotonic*
when the concentration of solute molecules inside and outside the cell are equal . Water diffuses into and out of the cell at equal rates. (Passive)
- Potato in tap water
- H2O moves in and out at same rate
- Potato stays same
facilitated diffusion*
Passive transport
is the diffusion of molecules across a cell membrane with the help of carrier proteins.
passive transport.
the carrier protein shields the molecules from the hydrophobic lipid bilayer.
ion channels
a membrane protein that gives a passageway across the cell membrane through which an ion can diffuse
sodium-potassium pump
Nerve cells (neurons) need to have a higher conc. of potassium ions inside and a lower conc, of sodium ions outside than in the fluid outside the cell. To do this the pump moves ions from an area of low concentration to an area of high concentration.
The sodium-potassium pump uses ATP (energy) to pump 3 Na+ out, pump in 2 K+
endocytosis
the process of engulfing large molecules in a membrane. The cell membrane makes a pocket around the molecule and breaks off inside the cell to form a vesicle.
Lysosomes may fuse with the vesicle and break down the molecules with enzymes.
a) Phagocytosis - means “cell eating”
- White blood cells engulf bacteria and destroy them as part of your immune system.
b) Pinocytosis - means ‘cell drinking.’
- the ingestion of fluid into the cell via endocytosis.
exocytosis-
the opposite of endocytosis.
the release of substances out of the cell (exit) by the fusion of a vesicle with the membrane.
Example: Sending the message along your nerves to move your toe requires exocytosis. Each time the message reaches the end of one neuron it must cross the gap between neurons. A vesicle carries the chemical or neurotransmitter from one neuron to the next via exocytosis.
What is the chemical equation for photosynthesis? (use words, not symbols)
Carbon dioxide + water + light energy —> organic compounds + oxygen
What is the chemical equation for cellular respiration? (use words, not symbols)
organic compounds + oxygen —> carbon dioxide + water + energy
What three chemicals do the light reactions produce?
NADPH, O2, ATP
Which two chemicals does the electron transport chain make?
NADH and Oxygen
From your notes, define chemiosmosis. What chemical does this process make?
Chemiosmosis is the process by which ATP is synthesized. It relies on a concentration gradient of protons across the thylakoid.
From your notes, define the Calvin Cycle. (dark reactions)
“The Dark Reactions” or more accurately “The Light Independent Reactions.”
Uses the energy stored in ATP and NADPH during the light reactions to produce organic compounds:
- named after an American scientist Melvin Calvin (1911-1997) who discovered its details.
- occurs in the stroma
Three steps of the Calvin cycle
Three Steps: occur in the stroma
1. CO2 combines with a carbohydrate (RuBP) to produce 2 PGA molecules.
- Each PGA molecule combines with parts of the ATP and NADPH molecules. This produces PGAL, ADP and NADP. The last two can be reused in the light reaction.
- Some PGAL molecules are used to make organic compounds. i.e. amino acids, lipids and carbohydrates.
Where do the light reactions occur? the dark reactions?
Light reactions: thylakoid
Dark reactions: stroma
From your notes, define carbon fixation.
The conversion of CO2 to organic compounds is known as carbon fixation
What three things does the rate of photosynthesis depend on?
Light intensity
Temperature
CO2 level
diagram (flow chart) that summarizes the stages of cellular respiration.
glycolysis-
A pathway in which ONE 6-carbon molecule of glucose is oxidized to produce TWO 3-carbon molecules of pyruvic acid.
- Takes place in the cytosol of the cell
- Cytosol: liquid located between cell membrane and nucleus of eukaryotic cells; organelles float and move in this
fermentation
a set of anaerobic (without oxygen) pathways in which pyruvic acid is converted into other organic molecules in the cytosol.
- Doesn’t produce ATP
- Regenerates NAD* (this helps keep glycolysis operating)
lactic acid fermentation
Lactic acid fermentation by microorganisms used to make yogurt and cheese
• Occurs in muscle cells during very strenuous exercise such as sprinting. Oxygen is used more quickly than it can be delivered and the muscle cells switch from aerobic respiration of lactic acid fermentation. Lactic acid accumulates in the cytosol and the increased acidity can cause pain, cramping and muscle fatigue.
• Eventually it diffuses back into the blood, and is converted back into pyruvic acid when oxygen becomes available,
alcoholic fermentation
Basis of wine and beer. Yeast cells are added to the fermentation mixture to provide the enzymes needed for alcoholic fermentation
* As fermentation proceeds, ethyl alcohol accumulates until it reaches a concentration that inhibits fermentation (wine approx 12%)
* CO2 escapes… result is table wines CO2 retained … result is champagne
* Bread making also relies on yeast cells.
The CO2 causes the bread to rise and the ethy! alcohol escapes during baking
Where does fermentation take place?
Cytosol
Where does aerobic respiration take place?
Mitochondria —> cristae
Just before the Kreb’s cycle, ________________
diffuses into the mitochondrial matrix. When it enters it reacts with an enzyme to form ____________
- pyruvic acid
- acetyl coenzyme A (acetyl CoA)
Summarize the Kreb’s cycle. (the * in your notes)
- Breaks down acetyl CoA to produce CO2, hydrogen, and ATP
- Named after Krebs- a German Jew
- 1 glucose molecule causes two turns of the Krebs cycle —> two turns produces 6NADH
- Krebs cycle produces 2 ATP
Where does the electron transport chain take place? How much energy does it make?
Occurs in the cristae (inner folds of the mitochondria) and makes 34 ATP molecules
Fill in the blanks:
Glycolysis makes ______ATP. Kreb’s Cycle makes _____ ATP and the electron transport chain makes ____ ATP. This makes a total of ____
ATP for aerobic respiration.
- 2
- 2
- 34
- 38
