Biology part 1 Molecules Flashcards

Question

Chromosomal translocation

Answer 1

when a segment of DNA from one chromosome is exchanged for a segment of DNA on another chromosome

Answer 2

the orientation of a section of DNA is reversed on a chromosome

Answer 3

when crossing over occur, the 2 chromosomes are zipped along each other where nucleotides are exchanged

Answer 4

under the light microscope, a synaptonemal complex appears as a single point where 2 chromosome are attached, creating an X shape

Answer 5

when genes on the same chromosome are located close together, they are more likely to cross over together, and are said to be linked

Answer 6

when crossing over occurs, the chromosomes may exchange sections of genetic information just once

Answer 7

when crossing over occurs, chromosomes may also trade a segment once and then trade back a sub-section of that segment so that each chromosome regains some of its own original genetic material

Answer 8

in the case of the female, one of the oocytes is much smaller and degenerates This occurs in order to conserve the cytoplasm, which is only contributed to the zygote by the ovum

Answer 9

if during anaphase I or II the centromere of any chromosome does not split one possible outcome of nondisjunction is having 3 copies of a single chromosome

Answer 10

Similar to the males, in the females the diploid oogonium undergoes mitosis to produce two primary oocytes. BUT unlike in males, this step in females primarily takes place before a female is born and the process does not proceed further until the female has reach puberty. Primary oocytes remain arrested in prophase I of meiosis I until they receive the hormone signal to participate in the menstrual cycle In meiosis 1 one daughter cell receives all of the cytoplasm and becomes a secondary oocyte, the other cell which receives no cytoplasm is the 1st polar body and discarded. The resulting secondary oocyte, now haploid, begins the process of meiosis II but is arrested at metaphase II. In this arrested state, the secondary oocyte completes meiosis II only when penetrated by a sperm during fertilization. The penetration initiates the completion of meiosis the completion of meiosis II, dividing the secondary oocyte into a second polar body, which is also discarded, and an ootid, which matures into an ovum

Answer 11

a spermatogonium (the diploid progenitor cell) undergoes mitosis to produce 2 diploid copies know as primary spermatocytes. Each primary spermatocyte undergoes the reduction division of meiosis I to become 2 haploid secondary spermatocytes. After the division of meiosis II, each secondary spermatocyte becomes 2 spermatids. A spermatid undergoes a process of maturation in which it loses its cytoplasm and gains a tail to become a mature male gamete called "sperm"

Answer 12

Diverges from glycolysis and eventually merges back at glyceraldehyde-3-phosphate. Its purpose is to create NADPH and some five carbon sugar, including ribose. This pathway is constitutively active. While it occurs to some extent in all tissues, it occurs most commonly in tissues involved in lipid synthesis, such as in the liver and adipocytes. This pathway is not regulated by an external hormone, but by NADPH, which inhibits the 1st step.

Answer 13

used in various synthetic functions of the body, such as making cholesterol, and also acts as an antioxidant.

Answer 14

liver cells have the unique property of being able to synthesize glucose from non-carbohydrate products, such as proteins and lactic acid. Almost a reversed pathway of glycolysis. Only a few reactions with large delta G have enzymes that are distinct from those of glycolysis. To be a substrate for gluconeogenesis, the substrate must have a 3-carbon backbone. Thus, while glycerol can be used, fatty acids can not. Some, but not all, amino acids can be used. Lactic acid can be used.

Answer 15

a polymer of glucose molecules linked by a-1,4 glycosidic bonds. Its primary substrate is glucose-6-phosphate Glycogen synthesis uses 1 UTP, thus does not require ATP. Instead an inorganic phosphate is enzymatically added to each a-1,4 bound glucose. Glycogen has an occasional a-1,6 glycosidic bonds that create side chains

Answer 16

promotes gluconeogenesis and glycogenolysis

Answer 17

can be used in 2 different ways in the body 1/ used directly by the organ into which they diffuse. broken down into acetyl-CoA via beta-oxidation 2/ in the liver, converted into a new molecule, called a ketone body, which can be shared with other organs for energy, = Ketogenesis Contain the greatest reducing potential per unit mass compared to carbohydrates and proteins

Answer 18

can be used in 2 different ways in the body 1/ used directly by the organ into which they diffuse. broken down into acetyl-CoA via beta-oxidation 2/ in the liver, converted into a new molecule, called a ketone body, which can be shared with other organs for energy, = Ketogenesis

Answer 19

2 steps: 1/ fatty acids => acyl-CoA, costing 1 ATP along the outer membrane of the mitochondria 2/ Acyl-CoA => mitochondrial matrix, where it is cleaved two carbons at a time to make acetyl-CoA, producing FADH2 + NADH for every 2 carbons taken from the original fatty acid. Acetyl-CoA then enters the TCA cycle. The glycerol backbone of the triglyceride is converted into an intermediate of glycolysis. Beta oxidation works well for even chain fatty acids, BUT odd chain end with a 3 carbon fatty acid. These 3 carbon molecule and glycerol can be substrates for gluconeogenesis.

Answer 20

3 primary ketone bodies in humans: acetone, acetoacetic acid, and beta-hydroxybutyrate Each of these is a small molecule with a carbonyl group, which allows them to dissolve in the blood stream via hydrogen bonding The purpose of ketone bodies is to spare glucose for the brain and red blood cells by providing an alternative source of energy for the other organs. HOWEVER, if needed the brain can use ketone bodies as an energy source as well. Ketogenesis takes place in the mitochondria of liver cells. Fatty acids enters the liver and is processed into ketone body. Ketone bodies are not substrates for gluconeogenesis. During starvation, energy for the livers come from fatty acids.

Answer 21

produced primarily in the liver, intestines, and adipcytes, and are expelled from these cells via exocytosis. These are the primary transport molecules that carry lipids from the intestines to the liver. The liver repackage chylomicrons as "very low density lipoproteins (VLDL) and high density lipoproteins (HDL).

Answer 22

special type of lipoproteins produced by the intestines, contains higher ratio of lipid to protein

Answer 23

transport lipids such as triglycerides, phospholipids, and cholesterol from the liver to the body, such as muscle and adipocytes

Answer 24

an enzyme that hydrolyzes triglyceries and releases free fatty acids into the bloodstream. Intestinal lipase tries to get triglycerides into cells. Hormone sensitive lipase tries to get triglycerides out of cells (adipocytes)

Answer 25

= protein formation. | Occurs during the fed state and should be associated with glycolysis, glycogenesis, and lipid storage

Answer 26

= protein breakdown Occurs during the fasting state and should be associated with gluconeogenesis, glycogenolysis, beta-oxidation, and ketone body synthesis. Begins with the hydrolysis of amino acid chains in the small intestines. Amino acids are connected by amide bonds, which can be hydrolyzed into an amine + carboxylic acid.

Answer 27

beings with the removal of the nitrogen group => producing ammonia + a carbon chain Amonia is fed into the urea cycle to become urea, which is excreted in the urine

Answer 28

ONLY can come from the intestines or the liver | Primarily regulated by insulin and glucagon, although epinephrine and cortisol are also involved.

Answer 29

ALWAYS require glucose Present a fixed and steady glucose demand Glucose is one of the few molecules that can penetrate the blood-brain barrier Red blood cells require glucose b/c they don't have mitochondria => their metabolism is limited to fermentation in the cytosol. All organs, except red blood cells, can also use ketone bodies for energy

Answer 30

the intestines are a source of abundant glucose When the supply of glucose coming from the intestines, metabolic pathways tends to use glucose and store excess glucose as glycogen and triglycerides = ALL organs will use blood glucose

Answer 31

The liver becomes the primary supplier of blood glucose This is nowhere near as abundant as that which comes from the intestines during and immediately after a meal. When glucose is being provided by the liver, metabolic pathways release glucose and fatty acids for use = Most organs will begin to use fatty acids from adipocytes

Answer 32

They have their own internal glycogen supply. They keep glucose produced from their glycogen stores for internal use rather than releasing it. They can use fatty acids as well.

Answer 33

released from the pancreas in response to increased blood glucose levels and promotes glycolysis in all tissues, glycogenesis in the liver and muscle, fatty acid synthesis in the liver, and fatty acid storage in adipocytes.

Answer 34

released from the pancreas in response to decreased blood glucose levels and promotes glycogenolysis in the liver and muscle, gluconeogenesis in the liver, fatty acid release in adipocytes, and beta-oxidation in almost all tissues

Answer 35

the absence of insulin promotes ketogenesis

Answer 36

is released in response to stress and, like glucagon, promotes glycogenolysis, the removal of glucose from storage.

Answer 37

is released in response to stress, but ONLY promotes gluconeogensis.

Answer 38

such as insulin, epinephrine, and glucagon have receptors on the outside of the cell membrane

Answer 39

such as cortisol, have receptors in the nucleus

Answer 40

in fasting state, red blood cells rely upon liver gluconeogenesis for their glucose supply. They do not have the enzymes necessary to produce glucose themselves. Red blood cells do not store glycogen, so they can't have glycogenolytic pathways active. They dont have mitochondria so they dont have the citric acid cycle. The pentose phosphate pathway is used to generate NADPH, which will be used to reduce glutathione in red blood cells.

Answer 41

Glycolysis slows down b/c ATP phosphorylates fructose 6-phosphate, which allosterically regulates phosphofructokinase

Answer 42

operates by brute force. It forces the ADP and phosphate group to join by smashing them together > positive delta G

Answer 43

occurs when oxidation reactions provide energy for phosphorylation

Answer 44

consists of 2 nucleotides joined together by phosphate groups NADH carries elections to the electron transport chain, acting as soluble electron carrier. The hydride ion serves as the source of electrons passed down the electron transport chain to oxygen, powering the movement of 3 x H+ into the intermembrane space of the mitochondria, empowering ATP synthase. Most NADH comes from the TCA cycle

Answer 45

is a coenzyme that transfers 2 carbons (from pyruvate) to the 4-carbon oxaloacetic acid to begin the TCA cycle

Answer 46

2 x carbons are lost as CO2, and oxaloacetic acid is regenerated Each turn of the cycle produces 1 ATP, 3 NADH, and 1 FADH2, + 2 CO2 1 glucose molecule powers 2 turns of TCA cycle Regulation is tied to the amount of NAD+ available

Answer 47

is a series of proteins that carries electrons from NADH to O2 These proteins include ubiquinone and cytochromes, which are intermediate electron carriers.

Answer 48

works in a similar fashion to NADH, except that FADH2 reduces a protein further along in the ETC series, and thus only about 2ATP are produced for each FADH2, as compared to 2-3 ATP for each NADH, depending on whether an ATP was spent to transport NADH into the mitochondrial matrix

Biology part 1 Molecules Flashcards

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