Midterm 1 Flashcards
Chemical reactions that occur in the human body proceed quickly due to the activity of specialized….
proteins
Which of the following is an example of a membranous organelle?
A) lysosome, B) glycosome, C) centriole, D) ribosome, E) cytoskeleton
A. lysosome
The beta cells of the pancreas produce insulin, a protein-based hormone. Which of the following organelles would be found at higher levels in the beta cells?
A) motochondria, B) ribosomes, C) mocrovilli, D) lysosomes, E) smooth endoplasmic reticulum
B. ribosomes
If the adrenal cortex produces lipid-based hormones such as aldosterone, which organelle would be more abundant in cells of the adrenal cortex than in the adrenal medulla?
A) golgi apparatus, B) mitochondria, C) ribosome, D) rough endoplasmic reticulum, E) smooth endoplasmic reticulum
E. smooth endoplasmic reticulum
What is the aerobic metabolism of glucose look like?
C6H12O6 + 6O2 –>6CO2 + 6H2O + 30ATP
In the aerobic metabolism of glucose, electrons that were once part of the glucose become part of a molecule of…
water H2O
What proteins extend all the way across the plasma membrane?
transmembrane
Many enzymes can undergo a process called phosphorylation. This allows them to be…
A) produced, B) temporarily activated or inactivated, C) permanently activated or inactivated, D) exported from a cell, E) broken down to produce ATP
B. temporarily activated or inactivated
List the 4 bases found in DNA and indicate which pair with which.
Adenine, Thymine, Guanine, and Cytosine
Adenine pairs with Thymine
Guanine pairs with Cytosine
List the 4 bases in RNA
Adenine, Guanine, Cytosine and Uracil
What is transcription?
The first step of gene expression, in which a particular segment of DNA is copied into RNA (mRNA) by the enzyme RNA polymerase.
Since Thymine is not a base of RNA, what does adenine copy into in transcription?
Uracil
Transcription of the DNA sequence ATC yields what?
UAG
Adenine - Uracil (not thymine)
Thymine - Adenine
Cytosine - Guanine
What is translation?
the process of translating the sequence of a messenger RNA (mRNA) molecule to a sequence of amino acids during protein synthesis. The genetic code describes the relationship between the sequence of base pairs in a gene and the corresponding amino acid sequence that it encodes.
What is the translation starting point?
starting codon: AUG
What is the translation end point?
stop codon: UAA, VAB, UGA
For each NADH molecule that contributes to the electron transport system, the yield of ATP molecules is about what?
2.5
Identify two high energy electron carriers used in metabolism`.
NAD & FADH
NAD -> (+e-) -> NADH
FADH -> (+e-) -> FADH2
ATP synthase transfers the (potential/kinetic) energy of the H+ ions to the high-energy phosphate bond of (NADH/ATP).
- kinetic
2. ATP
There are 2 basic types of reactions in cells. By definition those that release energy are called what? Those that require the input of energy are called what?
exergonic reaction - releases energy
endergonic reaction - require the input of energy
Oxidative phosphorylation occurs where? An end product of it is what?
Occurs in the mitochondria due to the electron transport system;
End product - ATP
Generally speaking, a specific enzyme will be able to catalyze:
A) a single type of reaction, B) a diversity of chemical reactions
A) a single type of reaction
A ribosome will not begin synthesizing a protein (or polypeptide) until it “reads” the codon…
AUG
Define the term catabolism as it applies to metabolism.
Reactions that release energy through the breakdown of large biomolecules.
Define the term anabolism as it applies to metabolism.
Energy-utilizing reactions that result in the synthesis of large biomolecules.
When an ATP molecule is “used” to power a chemical reaction it is converted into: (list the products)
ATP —> ADP + Pi + energy
The most important energy-transferring compound in cells is a nucleotide known as what?
adenosine triphosphate
Gluconeogenesis refers to…
production of glucose from glycerol, amino acids, or lactate
What metabolic pathways begin with the substrate of glucose? State whether they are anabolic or catabolic.
- Glycolysis: Glucose -> Pyruvate (catabolic)
- Glycogenesis: Glucose -> Glycogen (anabolic)
- Lipogenesis: Glucose -> Triglycerides (anabolic)
What metabolic pathways produce glucose? State whether they are anabolic or catabolic.
- Gluconeogeneis: Pyruvate, glycerol, some AA -> Glucose (anabolic)
- Glycogenolysis: Glycogen -> Glucose (catabolic)
What metabolic pathways involve fatty acids as their substrate or product? State whether they are anabolic or catabolic.
- Lipolysis: Triglycerides -> Fatty Acids & Glycerol (catabolic)
- Beta-Oxidation: Fatty Acids -> Acetyl-CoA (catabolic)
- Ketogenesis: Fatty Acids, some AA -> Acetyl CoA -> Ketone Bodies (anabolic)
An enzyme that digests fats would be…
lipase
About how many ATP molecules can be generated from 1 triglyceride?
300
Most of the CO2 that is generated in our cells is produced in/by what?
Citric Acid Cycle
Energy “lost” during metabolic processes is not really “lost.” It is converted to what?
heat
Which is NOT produced in the body specifically for the purpose of storing extra calories?
A) protein, B) lipids, C) carbohydrate
A. protein
Before converting amino acids into intermediates for energy metabolism, they must first undergo what?
deamination
The process of disassembling fatty acids into two-carbon units inside mitochondria is called what?
beta oxidation
Where in the cell does glycolysis take place? Is this and advantage or disadvantage?
Cytoplasm
Advantage because it’s fast since it is made where it is used.
What is the total net yield of ATP from glycolysis?
2 ATP
Glycolysis (all by itself) produces what? (include numbers)
2 Pyruvate
What is the starting substrate of the citric acid cycle? Where does it occur?
Acetyl CoA
Mitochondria matrix
How many ATP molecules are generated by “1 turn” of the citric acid cycle? What other molecules are generated (include numbers)
1 ATP
3 NADH
1 FADH2
What happens during fed state?
“use it! store it!”
glycogen is produced for storage
What happens during fasted state?
“mobilize!”
metabolic processes produce glucose to utilize for energy
Temperature is best defined as a measure of:
A) coldness, B) hotness, C) potential energy, D) kinetic energy, E) chemical energy
D. kinetic energy
During short-term fasting (hours), the energy stores of the what become the major source of glucose for body cells?
liver
The nutrients that yield the most energy per gram when metabolized are what?
fats
What are the 4 major types of biological molecules?
- Lipids
- Carbohydrates (sugars)
- Nucleic Acids
- Proteins
What are the general characteristics of lipids?
- Biomolecules made of mostly C and H
- Do not interact well with water or charged/partially charged molecules (hydrophobic)
- Do interact well with other lipids
- Used for stored energy (to make ATP from)
Describe the structure of a triglyceride.
3 fatty acids and 1 glycerol
Describe the primary structure of a protein.
linear chain of amino acids
If a cell’s membrane were made entirely of phospholipids what sorts of molecules could enter or leave the cell?
Oxygen, Carbon dioxide, and lipids (steroids) such as testosterone
Describe the structure of a steroid.
Molecules with four linked carbon rings
Describe the general structure of a carbohydrate.
Carbon with water
Which body cells are especially good at storing glycogen?
triglycerides
What are the 2 major subcompartments of the ECF and about what percent of the ECF does each contain?
plasma 25%
interstitial fluid 75%
Which organ is especially good at ketogenesis?
What is the starting substrate of ketogenesis?
Which larger molecules can be used to generate the starting substrate for ketogenesis? Explain how.
liver
Acetyl-CoA
Fatty Acids - fatty acids can be broken down to make acetyl-CoA during beta-oxidation.
What metabolic pathway could save your life? Why?
Ketogenesis because it makes ketone bodies which are an alternate energy source necessary for the CNS.
Describe in detail each of the components of a negative feedback loop control system.
- Stimulus - change in regulated variable
- Sensor - (neuron, endocrine cell) detects change in variable.
- Sensory input - the sensory signal/information that is sent to the…..
- Integrating Center - Receives sensory info, determines set point for the variable, compares/analyses info, makes a decision, and generates an……
- Output Signal - command that is sent to the….
- Target(s) Effector - a body structure that can influence the variable.
- Response - change in the variable to bring it back to set point.
List 5 body variables that are regulated by a negative feedback system.
- Body temperature
- Blood sugar concentration
- water balance
- pH
- Blood pressure
Describe a negative feedback loop for the regulation of body temperature.
Stimulus - increase in body temp Sensor - hypothalamus Input Signal - action potential Integrating Center - hypothalamus Output Signal - action potential Target/Effector - 1. increase activity of sweat glands; 2. vasodilation of cutaneous vessels Response - reduce in body temp
Describe glycolysis.
Glycolysis is a metabolic pathway that is catalyzed by enzymes which break down glucose to produce 2 pyruvate. The pyruvate can then be converted into Acetyl CoA and enter the citric acid cycle to produce a net gain of 2 ATP and @ NADH.
In reference to glycolysis, what is the alternate pathway used in the cell when oxygen is lacking or unavailable?
If oxygen is lacking the cycle stops and there is nothing to accept the hydrogen molecules and an alternate pathway must be used. The enzyme lactate dehydrogenate catalyzes a reaction to convert the pyruvate into lactic acid. In doing so it produces NAD which is able to accept the hydrogen and continue making ATP from the NADH.
What about glycolysis is considered an advantage? disadvantage?
Advantage: happens where it is used so the ATP doesn’t have to travel far and can be used immediately, alone it has a net gain of 2 ATP so can double very quickly, does not require oxygen.
Disadvantage: In comparison to aerobic catabolism which produces 30 ATP, 2 ATP is not many, glucose is a limited resource.
