IB BIOLOGY Flashcards
What is the name and role of NADH + H+ ?
- Nicotinamide adenine dinucleotide dehydrogenase (NADH)
- Hydrogen-carrying coenzyme/electron donor.
- NADH oxidises into NAD and liberates H+ and highly energised electrons in the beginning of electron transport chain.
- Hydrogen-carrying coenzyme/electron donor.
What are the 5 main parts of a chloroplast ?
Double membrane Starch Grain Grana Thylakoid Stroma
What are the 4 steps within Glycolysis ?
- Phosphorylation
- Lysis
- Oxidation
- ATP formation
What is the role of Thylakoids in chloroplasts ?
- Site of light dependent reactions
- large surface area to maximise light absorption
- Small space inside thylakoids allows for protein accumulation.
- the interior is acidic (Ph=4) high proton concentration allowing for chemiosmotic gradient
What does the entire aerobic respiration process have to intent ?
MAKE ATP SYNTHETASE WORK
ex. Humans need to breathe oxygen to maintain that hydrogen concentration gradient and keep ATP synthetase working.
What is the Krebs Cycle ?
Each acetyl group (CH3CO) formed in the link reaction yields : (1 turn of cycle) 2 CO2. 3 times NADH+ H+ 1 time FADH2 1 time ATP
What are the facts about stroma in chloroplasts ?
- site of light INDEPENDENT reactions
- stroma ph = 8/ basic when calvin cycle enzymes function optimally.
What is the role of Oxygen ?
- O enters aerobic respiration in final phase (ETC)
- responsible for maintenance of hydrogen concentration gradient between spaces separated by inner mitochondrial membrane
- Gradient promotes functioning of ATP synthetase (enzyme) and thus the phosphorylation of ADP to form ATP
- O Binds to free hydrogens to form water = hydrogen consumption keeps the hydrogen gradient and the proton traffic through the ATP synthetase.
Explain what Link reaction is :
In aerobic respiration (in mitochondria in eukaryotes) ech pyruvate is decarboxylated (CO2 removed).
The remaining 2carbon molecules (acetyl group) reacts with reduced coenzyme A, and, at the same time, one NADH+H+ (proton) is formed.
What is the relationship between the structure of the mitochondrion and its function ?
- Mitochondria are organelles that are involved in aerobic respiration in the cell.
- On their inner membrane (cristae) and in their fluid matrix are enzymes and materials needed for all stages of aerobic respiration = which produces ATP
- The cristae are folded to create more surface are so as to create more space for the electron transport chain to occur.
- There is so small space between inner and outer membranes for accumulation of protons.
What does reduction involve ?
- Gain in electrons
- Loss of oxygen
- gaining Hydrogen
What are the 3 main steps of Cell respiration ?
- Glycolysis
- Krebs Cycle
- Electron Transport Chain
What does oxidation involve ?
- Loss of electrons from an element
- Gaining oxygen
- Losing Hydrogen
What does the chloroplast membrane do ?
It is a double membrane regulating internal conditions
What happens in the Electron Transport Chain ?
- Electrons from NADH and FAD2 which are donated are passed through an electron transport chain to oxygen
- Which then combines with hydrogen to form Water
- Multi step reduction-oxidation (redox) process that occurs on the mitochondrial inner membrane
Describe the process of Glycolysis
- In the cytoplasm, one hexose (6 carbon) is converted into 2 three-carbons atom compounds (pyruvates) = GAIN of 2ATP and 2 NADH+ H+.
- In Phosphorylation, ATP loses 1 of its phosphates to the sugar to become ADP. This added phosphate makes sugar unstable and allows it to be broken down more easily.
- In Lysis, the 6 carbon molecule is split by enzymes into 2 three-carbon molecules of PGAL/G3P/TP. Each PGAL is then oxidised (Hydrogen ion removed and added to an ion carrier NAD+), which makes 2 molecules of NADH
What are the 3 facts about thylakoid membranes ?
- Hold photosystem pigments
2. Pigments anchor in thylakoid membrane by hydrophobic/Hydrocarbon tails
What are tumours the product of ?
uncontrolled cell division that occur in any organ or tissue.
What is cytokinesis in 2 words ?
cellular division
What are the 6 steps in Telophase ?
- Sister chromosomes have arrived at poles
- Spindle disappears
- Centrioles replicate
- Nuclear membrane becomes visible
- Nucleolus becomes visible
- Chromosomes decondense becoming chromatin
Recap of Prophase
The phase in mitosis in which the duplicated chromosomes condense, the nuclear envelope dissolves and centrioles divide and move to opposite ends of the cell.
What is interphase in a sentence ?
Active period in the life of a cell when many metabolic reactions occur, including protein synthesis, DNA replication and an increase in the number of mitochondria and/or chloroplasts.
What are the 3 steps in Interphase ?
- G1 : Growth, protein synthesis, increase in the number of mitochondria and/chloroplasts
- S : DNA replication
- G2 : Growth,protein synthesis, preparation for mitosis/cytokinesis.
Recap of Interphase
The phase of a cell’s life where DNA is repicated
Recap of Anaphase
The phase in mitosis in which chromosomes begin to separate.
What are the 5 main steps in Prophase ?
- Chromosomes condense by supercoiling becoming visible.
- Centrioles move to opposite poles
- nucleolus disappears
- Nuclear membrane disappears
- Microtubular spindle apparatus form at each poles.
What 4 other processes involve mitosis ?
- Growth
- Embryonic development
- Tissue repair
- Asexual reproduction
How does mitosis produce 2 genetically identical nuclei ?
- DNA replication during S phase of interphase produces 2 identical copies of DNA.
- Identical sets of DNA are attached to each other as sister chromatids of each of the cell’s chromosomes.
- Mitosis segregates the two chromatids of each chromosome to opposite poles, forming two identical nuclei, each with one complete copy of the original DNA.
- Cytokinesis separates the two daughter nuclei into identical daughter cells.
What is mitosis in 2 words ?
nuclear division
What are the 2 main steps in Metaphase ?
- Spindle microtubules attach to chromosomes centromeres
2. Chromosomes move to the equator
Give a complete definition of Mitosis
Mitosis is the duplication and division of a eukaryotic cell’s nucleus and nuclear material (DNA). The stages of mitosis are : Interphase, Prophase, Metaphase, Anaphase and Telophase.
What are the 2 steps in Anaphase ?
- Centromeres split as spindle microtubules pull chromatids to opposite poles (after centromeres split sister chromatids become sister chromosomes)
- Sister chromosomes move to opposite poles as microtubules shorten.
Recap of Metaphase
The phase in mitosis in which chromosomes line up at the equator (central plane of the cell).
What are the 5 phases of cell division ?
- Interphase
- Prophase
- Metaphase
- Anaphase
- telophase
Recap of telophase
The last phase, when the chromosomes migrate to opposite ends of the cell, two nuclear envelopes form, and the chromosomes uncoil.
List the 6 functions of membrane proteins
- Hormone binding sites
- Immobilised enzymes
- Cell adhesion
- Cell to cell communication
- Channels for passive transport
- Pumps for active transport
What is the composition of a plant cell wall ?
Cellulose microfibrils
What does Protein synthesis do in the transport of material in a cell ?
RER produces proteins which travel through the lumen (gap in tube) of the ER.
What are the 5 main parts of a membrane ?
- Phospholipid bilayer
- Cholesterol
- Glycoproteins
- Integral proteins embedded in the phospholipid of the membrane.
- Peripheral proteins attached to the phospholipid surface
What are the main features of the phospholipids (head) ?
- Polar
- Hydrophilic
- They make the outside of the phospholipid layer
What is simple diffusion ?
Travelling directly through the membrane if they are small and uncharged, thus avoiding repulsion by the hydrophobic, non polar tails of phospholipids in the middle of the membrane.
Explain how phospholipids work to form a membrane ?
Because one end of the phospholipid is Hydrophilic and the other is Hydrophobic, they naturally form bilayers in which the heads are facing outwards and the tails are facing inward.
STABLE STRUCTURE IS FORMED
What are the 3 main parts of a plant cell that animal cells lack ?
- Cellulose wall
- chloroplasts
- Large central vacuole
How are vesicles transported ?
Membrane produced by the RER flows in the form of transport vesicles to the Golgi, carrying proteins within the vesicles.
What are the 2 main facts about protein pumps ?
- Integral protein pumps embedded within membrane
2. Specific to molecule transported.
How do protein pumps get the energy from ?
- usually provided by ATP
2. Often by phosphorylating the protein pump as ATP is hydrolysed.
How does the modification process work ?
Golgi apparatus modifies proteins produced in ER