DNA Replication Flashcards
What make up a DNA nucleotide?
Phosphate Group: This part of the nucleotide links the sugar of one nucleotide to the sugar of the next nucleotide, forming the backbone of the DNA strand.
Deoxyribose Sugar: A five-carbon sugar molecule that is part of the DNA backbone. It is called “deoxyribose” because it lacks an oxygen atom that is present in ribose (found in RNA).
Nitrogenous Base: There are four types of nitrogenous bases in DNA—adenine (A), thymine (T), cytosine (C), and guanine (G). These bases pair specifically (A with T, C with G) to form the rungs of the DNA double helix.
What stabilizes the DNA strands as they unwind?
single strand- binding proteins
stabilizes before replication by preventing reannealing so that the strands can serve as template
What is the role of primase in DNA replication?
synthesizes RNA primers for DNA polymerase
What is the role of DNA polymerase III in DNA replication?
synthesizes DNA by adding nucleotides to the new DNA strand
When does DNA replication occur?
DNA replication occurs during the S phase (Synthesis phase) of the cell cycle. This phase takes place before cell division, ensuring that each daughter cell will receive an identical copy of the DNA.
In the cell cycle, the S phase follows the G1 phase (growth phase) and precedes the G2 phase (preparation for mitosis).
If the template strand reads AGGTCC, what is the newly formed DNA?
TCCAGG
What is the role of polymerase I?
removes RNA primers and replaces with DNA
What are 3 things needed for cellular respiration and ATP production
Glucose: Serves as the primary fuel source that is broken down to release energy.
Oxygen: Acts as the final electron acceptor in the electron transport chain, allowing for the production of a large amount of ATP.
Enzymes: Facilitate the chemical reactions involved in breaking down glucose and synthesizing ATP.
what is the role of the three enzymes in glycolysis?
Hexokinase:
Role: Catalyzes the first step of glycolysis, where it phosphorylates glucose to form glucose-6-phosphate.
Significance: This step helps trap glucose inside the cell and prepares it for further breakdown.
Phosphofructokinase (PFK):
Role: Catalyzes the third step of glycolysis, converting fructose-6-phosphate to fructose-1,6-bisphosphate.
Significance: It is a key regulatory enzyme and is considered the rate-limiting step of glycolysis, meaning it controls the speed of the pathway. It is regulated by energy levels (e.g., ATP levels) in the cell.
Pyruvate Kinase:
Role: Catalyzes the final step of glycolysis, where phosphoenolpyruvate (PEP) is converted to pyruvate, producing ATP.
Significance: This step generates ATP and completes the process of glycolysis, providing pyruvate for further energy production under aerobic or anaerobic conditions.
When oxygen is not present, what is pyruvate converted into?
When oxygen is not present, pyruvate is converted into:
Lactate (lactic acid) in animal cells (including human muscle cells) through a process called lactic acid fermentation.
Ethanol and carbon dioxide in yeast and some bacteria through a process called alcoholic fermentation.
What are the three processes in cellular respiration?
Glycolysis:
Occurs in the cytoplasm.
Breaks down glucose into two molecules of pyruvate, producing a small amount of ATP and NADH.
Citric Acid Cycle (Krebs Cycle):
Takes place in the mitochondrial matrix.
Processes acetyl-CoA (derived from pyruvate) to produce NADH, FADH2, and ATP, while releasing CO2.
Electron Transport Chain (ETC):
Located in the inner mitochondrial membrane.
Uses NADH and FADH2 to transfer electrons through a series of proteins, creating a proton gradient that drives the production of ATP via oxidative phosphorylation.
what are the inputs and outputs of cellular respiration?
GLYCOLYSIS:
INPUTS:
1 glucose
2 NAD+
2 ATP
4ADP + 4 Pi (PHOSPHATE GROUPS)
OUTPUTS:
2 PYRUVATE
2 NADH
4 ATP (NET OF 2 ATP_
PREPATORY PHASE:
INPUT:
NAD+
OUTPUT: CO2
NADH
ACETYL COA
CITRIC ACID CYCLE:
INPUT:
ACETYL-COA
6 NAD+
2 FAD
2 ADP+2 pi
output (TWO TURNS):
4 CO2
6 NADH
2 FADH2
2 ATP
ETC:
INPUT: NADH
FADH2
O2 FINAL ELECTRON ACCEPTOR
ADP+Pi
OUTPUT :
APPRX 34 ATP
H2O
NAD+ and FAD
NET :
AROUND 36-38 ATP
What is the advantage to using fats for energy?
Fats contain more than twice the amount of energy (calories) per gram compared to carbohydrates and proteins. This makes them an efficient energy source, especially for long-term energy storage.
-Fats can be stored in a compact form in adipose tissue, providing a large energy reserve without significantly increasing body weight.
-Fats are broken down more slowly than carbohydrates, leading to a steady release of energy, which is ideal for endurance activities and maintaining energy levels over a longer period.
the first 5-10 seconds of exercise what are we using ?
phosphagen (creatine phosphate and ATP)
- it is short lived because phosphocreatine stores deplete quickly
What is allosteric control?
Allosteric control is the regulation of an enzyme’s activity through the binding of a molecule at a site other than the enzyme’s active site (called the allosteric site). This binding changes the enzyme’s shape, either increasing or decreasing its activity.
