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30

(Cells Part 3 : Meiosis)
Directly after what stage of meiosis are four non-identical daughter cells produced?
(A) Anaphase I
(B) Metaphase II
(C) Prophase II
(D) Telophase II

ANSWER
(D) Telophase II

31

(Cells Part 3 : Meiosis)
Which cell division process would be used after fertilization, to begin creating the tissues, organs,cans body systems of the developing fetus?
(A) Mitosis
(B) Meiosis

ANSWER
(A) Mitosis

32

(Genetics Part 1 : Mendel's Principle of Segregation)
What is a gene? What is an allele?

- gene :
- unit of heredity that is transferred from a parent to offspring and is held to determine some characteristic of the offspring
- code for specific trait
- allele :
- one of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome
- examples : hair color, eye color

33

(Genetics Part 1 : Mendel's Principle of Segregation)
What does it mean to say an allele is dominant or recessive?

- dominant :
- heterozygous
- an allele that produces the same phenotype (set of observable characteristics) whether it's paired allele is identical or different
- example : allele for brown eyes,
- recessive :
- homozygous
- only show their effect if the individual has two copies of the allele
- example : allele for blue eyes

34

(Genetics Part 1 : Mendel's Principle of Segregation)
What does it mean to say an organism is heterozygous or homozygous?

- heterozygous : organisms whose cells contain two different alleles of a given gene, only shows dominant trait
- homozygous : organisms whose cells contain two identical alleles of a given gene
Example : a gene for curly hair is 'C' and a gene for straight hair is 'c', dominant trait is capitalized and recessive trait is smaller letter; for a person to have curly hair, they need to have a pairing of CC or Cc since they both contain dominant trait, C for curly hair; in order for a person to have straight hair they need to have a pairing of cc because it is pure recessive

35

(Genetics Part 1 : Mendel's Principle of Segregation)
What is genotype? What is phenotype?

- genotype :
- genetic makeup of an organism or group of organisms with reference to a single trait, set of traits, or an entire complex of traits
- set of genes in our DNA which is responsible for a particular trait
- phenotype :
- an individual's observable traits
- examples : height, eye color, blood type

36

(Genetics Part 1 : Mendel's Principle of Segregation)
What is Mendel's Principle of Segregation?

- states that each hereditary characteristic is controlled by two 'factors' (now called alleles) which segregate and pass into separate germ cells

37

(Genetics Part 2 : Mendel's Principle of Independent Assortment)
What is Mendel's Principle of independent assortment?

- states that pairs of 'factors' segregate independently of each other when germ cells are formed

38

(Genetics Part 2 : Mendel's Principle of Independent Assortment)
How does the process of meiosis contribute to independent assortment?

- meiosis splits the gene pairs into individual genes for packaging into the reproductive cells (egg and sperm)
- when the reproductive cells are combined, these genes are re-combined into new pairs, thus leading to better/greater diversity of gene expression

39

(Genetics Part 2 : Mendel's Principle of Independent Assortment)
How does crossing over contribute to independent assortment? How can it promote genetic variation?

- crossing over occurs when the homologous chromosomes are lined up at the equatorial plane and some chromosome exchanges corresponding parts with its homologue
- causes the chromosomes of the dividing cell to no longer be identical to ones in the parent cell
- results in chromosomes being composites of the two homologous parent chromosomes
- results in recombination - production of new combination of genes different from those in parental chromosomes
- occurs at different points in meiosis division - produces lots of genetic variation
- only in meiosis
- results in recombination
- produces new concentrations of genes
- different from the parents' combinations
- only apparent with heterozygous so genotypes

40

(Genetics Part 3 : Mutation and Radiation)
What is a chromosome?

- threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes

41

(Genetics Part 3 : Mutation and Radiation)
What causes genetic mutations?

- occurs when the sequence on nucleotides (A,C,G,T sequence) in an organisms DNA is changed
- can be from errors during DNA replication or exposure to mutagens (mutation causing agents) for example : uv light, x-rays, chemicals
- ultimate source of all genetic variation and provide raw materials for evolution and natural selection
- can be inherited, or acquired

42

(Genetics Part 3 : Mutation and Radiation)
How does ionizing radiation from radioactive materials damage the DNA?

- when it strike electrons in the body with enough energy, electrons are freed from the atoms they were orbiting
- free electrons then strike and damage DNA directly
- more frequently - damage occurs indirectly when freed electrons hits water molecules in a cell producing free radicals (group of atoms that has an unpaired electron and is consequently unstable and highly reactive)
- free radicals race with wide variety of molecules in the body - including DNA
- interactions with DNA damage it, causing 1 or more genetic mutations
- frequently dividing cells are more vulnerable to radiation damage
- ionizing radiation : UV, X-rays, nuclear radiation

43

(Genetics Part 3 Mutation and Radiation)
Why are bone marrow cells and cells in the gastrointestinal tract more vulnerable to radiation damage?

- because of the water that makes up most of the cells volume is affected and carried throughout the whole body

44

(Genetics Part 3 : Mutation and Radiation)
Why do ultraviolet radiation and radon cause cancer?

- ultraviolet radiation : from the sun/sun exposure; the melanin absorbs the dangerous UV rays that cause cancer; leads to breaks in the strand of DNA
- radon : because it's radioactive gas that is released in rocks and soil; radioactive particles from radon can damage cells that line the lungs and lead to lung cancer; radon is the 2nd leading cause of lung cancer in the USA

45

(Studying Organisms Part 1 : Hierarchy of Organ Systems)
Describe how cells, tissues, organs, and organ systems work together to perform human body functions.

- cells : living organism
- tissues :
- groups of specialized cells performing specific functions
- four types : epithelial, connective, muscular, nervous
1) epithelial : lines all surfaces, on the outside its protective, on the inside they absorb nutrients, excretes mucus that lubricates the inner surfaces of the body
2) connective : ranges from very, very hard tissue, like bone to very, very liquidy tissue like blood, in between we have cartilage, tendons, and ligaments that hold our bodies together, connects one part of the body to another, has living cells imbedded in some sort of matrix surrounding protein material, in tendon or ligament fibers run parallel creating a rope like structure, in cartilage they are a gelatinous matrix with some fibers to give strength
3) muscular : striated muscle helps arms and legs move, sometimes called skeletal muscle, not connective tissue, function is to contract or shorten to move body, smooth muscle inner body helps keep food in stomach moving, cardiac tissue in the heart strongest most enduring, never rests
4) nervous : two types of cells - neuroglial cell are supportive, helping cells that help neurons do their job and neurons job is to carry electrochemical signals throughout the body, neurons carry signals very rapidly from the brain out to farthest riches and back again
- organ :
- groups of different types of tissues working together to perform a more general function
- example : stomach
- organ systems :
- group of organs that work together that perform a larger, more general purpose
- example : digestive system

46

(Studying Organisms Part 2 : Homeostasis)
How does our body maintain homeostasis? Include examples of how our body maintains homeostasis when there are fluctuations in conditions such as temperature, hydration, and glucose blood levels.

- the way that our bodies or any living things body coordinates its activities to maintain certain things at certain levels
- temperature :
- when cold, body shivers which means that body temperature has dropped below the level that is comfortable
- signals will go into the central nervous system from all the temperature sensors out in the skin and in the tissues of the body carrying the message
- the brain and spinal cord will send signals out to the other parts of the body to get a response to raise body temperature back to a comfortable
- the circulatory system might respond by contracting blood vessels near the surface of the skin smaller so that more blood is retained near the core of the body, particularly in the toes and fingers which will have less circulation
- the muscular system will respond by shivering, tiny contractions of muscles which generate heat
- endocrine system will respond if cold for long periods of time, might be hormones (chemical messengers that are sent out to tell the whole body to change its metabolism)
- winter time might affect the digestive system, you might be more hungry so that you'll eat more food providing your body with more fuel to excess heat that's needed to keep your temperature up during cold winter temperatures.
- if it gets too hot, the nervous system would detect that and send signals out to the other systems
- the epithelial or skin might respond by producing sweat, moisture on the surface of the skin that would evaporate and cool body temperature down
- the circulatory system, again would send more blood out to the skin where it can cool off by the evaporation action of the epithelial system
- and again, when the temperatures brought back down to a comfortable level it will shut off
- glucose blood levels :
- if blood sugar level gets too high, a series of reactions will happen in your body to bring it back down
- if it gets too low, the opposite kinds of things will happen to bring your blood sugar up into range that is comfortable for the body

47

(Studying Organisms Part 3 : Nervous, Circulatory, and Respiratory)
Describe the cells, tissues, and organs for the nervous system. Explain how the neurons, spinal cord, and brain work together to respond to stimuli. How does this help the body maintain homeostasis?

- NERVOUS SYSTEM
- Cells
1) neurons :
- cells that carry signals around the body, electrochemical signals
- has a cell body with a nucleus and other organelles
- have special, branching hair-like processes called dendrites
- dendrites receive signals, either from other neurons or from outside world that are sent in towards the cell body on a long process called and axon
- axon carries signal our towards other neurons at the axon terminals or also effectors (things that respond to nervous signals, like for example muscles)
2) neuroglial cells : supportive cells that help nourish, feed, and protect the neurons
Organ Systems
- Central Nervous System
- composed of brain and spinal cord
- composed on inter neurons
- is where decisions are made, where signals are sent on, where learning takes place in all of our higher thought processes (in cerebrum)
- cerebellum : location for motor control
- keeps your body coordinated
- handles movements that you don't have to think about (walking)
- brain stem : upper part of spinal cord where attaches to brain
- several important pieces that are responsible for basic life functions like heartbeat, respiration, gag reflex, hiccups, coughing
- carries signals to and from the rest of the central nervous system
- controls reflexes
Peripheral Nervous System
- motor and sensory neurons
- two parts :
1) Somatic - voluntary functions and sensory inputs
2) Autonomic - involuntary functions and internal organs
- sympathetic : "fight or flight"
- parasympathetic : "rest and digest"

48

(Studying Organisms Part 3 : Nervous, Circulatory, and Respiratory)
Describe the cells, tissues, and organs of the circulatory system. Explain the functions of the cells, heart, arteries, and veins of the circulatory system in transporting oxygen and carbon dioxide throughout the body. How does this help the body maintain homeostasis?

CIRCULATORY SYSTEM
- Consists of the heart, blood vessels, and blood
- heart is the pump and connects the blood vessels which contain blood which is always contained in vessels
- three types of blood vessels :
1) arteries - carry blood away from the heart
2) veins - carry blood back towards the heart
3) capillaries - tiny, tiny little blood vessels that connect the arteries and veins, and are so small they travel in single file line, penetrate all tissues of the body, exchange of materials that are carried in blood with materials is the tissue occurs
- carries oxygen and nutrients, and drops carbon dioxide and waste to be disposed of
- blood consists of red blood cells (shaped like donut) that carry oxygen around the body; white blood cells (clear or translucent) plan important role in immune system; plasma is fluid that contains important proteins and carries most of the wastes, carbon dioxide, and nutrients

49

(Studying Organisms Part 3 : Nervous, Circulatory, and Respiratory)
Describe the cells, tissues, and organs of the respiratory system. Explain how the cells, tissues,can't organs in the respiratory and circulatory system function interdependent lay to provide cells with oxygen. How does this help the body maintain homeostasis?

RESPIRATORY SYSTEM
- Composed of your nose, trachea, and the structures in your lungs
- breathe in through your nose, it goes into nasal cavity (sinuses where air is filtered and warmed)
- then passes through pharynx or throat into the larynx (voice box) down the trachea, which is held open by rings of cartilage (windpipe)
- air then passes either into your right or left lung through the bronchi which branch down into tinier and tinier branches called bronchioles
- finally end in tiny air pockets called alveoli, which are surrounded by capillaries
- capillaries drop off carbon dioxide into alveoli and pick up oxygen from alveoli that carry back to the heart and then back out of the body
- diaphragm : muscle across base of chest cavity when it contracts it gets straighter and flatter and that increase the area in chest cavity
- when relaxed, it bends into a U shape which pushes air back out

50

(Studying Organisms Part 4 : Digestive, Excretory, and Immune Systems)
Describe how the cells, tissues, and organs associated with the digestive system break down food. How does this help the body maintain homeostasis?

DIGESTIVE SYSTEM
- we get hungry, we eat
- plays role in the body of obtaining food, extracting nutrients from food, and eliminating waste from the body
- consists of salivary glands in the mouth, the teeth and tongue that help to break up the food.
- once food is moistened by saliva and partially broken up by the teeth and the tongue, we swallow the food down our throat (pharynx)
- once swallowed, it continues down through the digestive tract through waves of muscular motions called peristalsis and are involuntary motions that keep the food moving.
- there are waves of peristalsis throughout all tubes of digestive system
- food passes down esophagus into the stomach
- stomach is muscular chamber that continues to slosh and mush food, acids are added kill some of the bacteria that might be on the food and help activate enzymes that are present in the stomach to begin the digestion of proteins
- food leaves the stomach in a very liquidy format through the duodenum, which is the first section of the small intestine (about as big as the diameter of your finger)
- small intestine very small, but very long and digests majority of food; enzymes are released into small intestine from the pancreas and gall bladder, these enzymes are designed to digest specific portions of food, some digest carbohydrates, starches and things like that, while others digest fats and others digest proteins, food is chemically broken down in small intestine and nutrients are absorbed into the blood through a massive system of capillaries that surround the small intestines; interior is lined with finger-like projections called villi which increase surface area and make it effective for absorption.
- peristalsis continues moving the contents until the empty into the large intestines
-large intestine goes up and across and down and ends in the rectum which is a storage pouch; most of what is occurring is liquid, the water that remains in the contents are reabsorbed into the body so the contents of the large intestine are mostly undigestible waste; by the time the contents of the large intestine reach the end it's pretty much wastes that have been compacted and dried into the feces that will leave the body through the anus.
- near where the large and small intestine join together there's a little finger-like blind pouch called the appendix
- appendix doesn't really serve any digestive purpose; it does have a lot of bacteria in it and if those bacteria get out of control and it becomes infected and inflamed it can be life threatening so it would have to be removed

51

(Studying Organisms Part 4 : Digestive, Excretory, and Immune Systems)
Describe how the cells, tissues, and organs in the urinary system aid in eliminating waste from the body and maintaining water balance. How does this help the body maintain homeostasis?

EXCRETORY SYSTEM (URINARY)
- removes metabolic wastes from body
- these wastes are produced by the breakdown of molecules in your body and deposited in the blood
- wastes are ammonia and related molecules and are toxic to the body and have to be filtered out, if levels get too high, it would be dangerous
- kidneys are the blood filters that filter toxic products and other types of wastes out of the blood; blood enters the kidney into small capillaries where all of the liquid stuff in the blood is forced out into a tube called the nephron (tens of thousands in kidney) and is colored yellow and surrounded by capillaries that drop off waste products and the blood can be cleared and purified
- kidneys are connected by ureters
- ureters are tubes that drain into the bladder, it's storage pouch for the waste products, and the urethra is how the wastes leave the body
- one of the major functions of the urinary system is to control the water/salt balance or the blood pressure in your body
- if you have high blood pressure, you'll lose more water through your urine, that's to lower blood pressure
- if your blood pressure is low, your kidneys are going to work very hard to extract as much water as possible out of the nephron which extracts salt
- contents of nephron then travel through the distal convoluted tube, which removes large molecules that didn't get filtered out which ends up as urine
- as urine travels down the collecting duct and heads towards the ureters, more water can be pulled out of it to concentrate the urine
- the darker the urine, the more concentrated the urine

52

(Studying Organisms Part 4 : Digestive, Excretory, and Immune Systems)
Explain the role of cells, tissues, and organs in the acquired immune response.

IMMUNE SYSTEM
- consists of lymph nodes and lymph vessels that are scattered throughout the body
- clustered in certain places where you might occasionally fell them if they become sore like your armpits or your groin
- the tonsils in the neck are the glands in your neck that become swollen when you have a sore throat and some of the other lymph nodes that are located in the neck and head sometimes are easy to locate if they become swollen and sore
- lymph vessels contain fluids, body fluids, and those fluids that are filtered through the lymph nodes which are places where white blood cells hang out in the body
- white blood cells are produced in the bone marrow and some of them mature in the thymus that act as policemen or soldiers of the body by monitoring fluids that flow through the lymph nodes for any foreign invaders or anything that looks suspicious and attack it; also are traveling in the blood and are constantly checking for foreign invaders or things that look not quite normal in the body and they attack and clean those things up
- the spleen is a large filtering organ that the blood flows through; many white blood cells hang out in the spleen and are monitoring the blood as it flows through the spleen filtering it for dead cells, irregular cells, other kinds of problems that might be in the blood
- your skin acts as a barrier; it prevents most of the things that are trying to make you sick from getting into your body in the first place, but doesn't always work
- pathogens = things that might make you sick
- first offense for against pathogens is the innate Immune system; say you get punctured by a thorn, these little bacteria (purple rod shaped things) that have entered through the break in the skin; when the skin is broken, little alarm chemicals called histamines are released into the body and they call white blood cells to the site of the injury; the white blood cells gather and attack the bacteria engulfing them actually eating them to destroy them
- histamines also cause the blood vessels int the area to widen so that they can carry more blood to the area, the area gets hot, red and swollen
- another specific reaction occurs called acquired immune system
- acquired immunity works against viruses
- example : when Chicken Pox first invades, the virus is able to invade individual cells and hide inside those cells so that most of the white blood cells in your body aren't able to recognize that an invasion is occurring, until the b white blood cell and t white blood cell finds the chickenpox the body won't attack the invasion, but once it does get recognized, it bursts into action by quickly dividing over and over again to produce special plasma cells that release antibodies (y shapes protein that attacks virus)
- the chicken pox had time to make you sick before this happened and it takes a little while for the b and T cells to clean it up and you get better
- once you get better, b and T cells start to die off but some don't die and are left behind as memory cells and these cells are like an army that's waiting in reverse ready if you're ever invaded by the Chicken Pox again
- there's also a bunch of antibodies left behind, so next time the chicken pox virus gets into your system, these memory cells and antibodies are able to attack it and kill it before it has a chance to make you sick and that why you don't get sick again with Chicken Pox
- the same thing occurs with immunizations, the immunization tricks your body into producing an army of antibodies and b and T cells and the memory cells that you need to fight off the real virus if you're ever exposed to it

53

Quiz A
What is a catalyst in a chemical reaction?

- A substance that speeds up a chemical reaction by lowering its activation energy.
- A catalyst is a substance that increases (speeds up) the rate of a chemical reaction by lowering its activation energy. A catalyst also remains chemically unchanged in a chemical reaction. Enzymes are examples of biological catalysts, important in chemical reactions common to living systems.

54

Quiz A
What best describes a difference between photosynthesis and cellular respiration?

- Photosynthesis converts solar energy into chemical energy, whereas cellular respiration converts chemical energy in glucose into a more useable form.
- During photosynthesis, solar energy is converted into chemical energy that is stored in glucose. During cellular respiration, glucose is broken down to release the stored energy so that it can be used for various life processes.

55

Quiz A
How is a eukaryotic cell different from a prokaryotic cell?

- A eukaryotic cell contains a nucleus, but a prokaryotic cell does not.
- A key difference between eukaryotic ("true nucleus") and prokaryotic ("before nucleus") cells is that eukaryotic cells contain a nucleus.

56

Quiz A
What is the main function of the respiratory system in humans?

- exchange of gases with the environment
- The respiratory system (the mouth and nose, trachea, and lungs) is the body system that is primarily responsible for gas exchange. Inside then lungs, carbon dioxide leaves the bloodstream and oxygen enters the bloodstream.

57

Quiz A
What is a characteristic of mitosis?

- It occurs in body (somatic) cells
- Mitosis is a form of body cell division in which one parent cell divides into two daughter cells that contain re same genetic information as the parent cell.

58

Quiz A
A scientist observes a cell under a microscope and concludes that it is a eukaryotic cell. What did the scientist most likely observe that led to this conclusion?

- the presence of mitochondria and chloroplasts in the cell
- Eukaryotic cells contain membrane-bound organelles, such as mitochondria and chloroplasts and a nucleus.

59

Quiz A
What does Mendel's Law of Segregation state?

- an individual inherits an allele for each trait from each parent and during gamete formation the alleles inherited are a matter of chance
- Mendel put forth that heritable factors that determine traits consist to two alleles, one inherited from each parent. This is known as Mendel's law of segregation.