Bio exam 2

9.1.d. Distinguish between the following pairs of terms used in genetics; (a) genotype and phenotype. (b) dominant and recessive(c) homozygous and heterozygous. Use 1 term from each pair to describe a human trait.

(a) Genotype refers to the genetic makeup of an organism, while phenotype refers to the physical characteristics or traits that are expressed as a result of the genotype. Genotype determines the phenotype, but the phenotype can also be influenced by environmental factors. Example: Eye color in humans is determined by the genotype, but the phenotype (the actual color of the eyes) can be influenced by environmental factors like lighting and reflection. (b) Dominant and recessive refer to the two possible alleles or variants of a gene, where the dominant allele expresses its trait and the recessive allele is only expressed in the absence of a dominant allele. Example: Tongue rolling is a dominant trait, and non-tongue rolling is a recessive trait in humans. (c) Homozygous refers to having two identical alleles for a particular gene, while heterozygous refers to having two different alleles for a particular gene. Example: Cystic fibrosis is a genetic disorder caused by a recessive allele. A person who is homozygous recessive (has two copies of the recessive allele) will have cystic fibrosis, while a person who is heterozygous (has one copy of the recessive allele and one copy of the dominant allele) will not have cystic fibrosis but can still pass on the recessive allele to their offspring.

Hermaphroditism

A condition in which an individual has both female and male gonads and functions as both a male and female in sexual reproduction by producing both sperm and eggs.

10.2.a. What is a gene? Outline the flow of genetic information in a eukaryotic cell.Which processes link together the three stages?

A gene is a segment of DNA that contains the instructions for the production of a specific protein or RNA molecule. In eukaryotic cells, genetic information flows from DNA to RNA to protein. The first stage is transcription, where DNA is used as a template to create a complementary RNA molecule. This process occurs in the nucleus and is catalyzed by the enzyme RNA polymerase. The RNA molecule produced is called messenger RNA (mRNA), and it carries the genetic information from the DNA to the ribosome. The second stage is translation, where the information carried by the mRNA is used to synthesize a protein. This process occurs in the cytoplasm and is carried out by ribosomes, which read the sequence of the mRNA and assemble amino acids in the correct order to form a protein. The third stage is post-translational modification, where the protein undergoes modifications to become fully functional. This process can involve folding, cleavage, and chemical modifications such as the addition of sugar or lipid groups. The processes that link these three stages include RNA processing, where the initial RNA molecule is modified before it can be used for translation, and protein targeting, where the protein is directed to its final destination within the cell.

9.1.c. What is a monohybrid cross? Distinguish between the P, the F1 and the F2 generations?

A monohybrid cross is a type of genetic cross between two individuals that differ in only one trait or gene. In this cross, the offspring of the two parents are analyzed to study the inheritance pattern of a single trait. The P generation (parental generation) refers to the two individuals that are crossed to produce the offspring in the first generation, or F1 generation. The F1 generation (first filial generation) refers to the offspring of the P generation, which are all hybrids, or heterozygous for the trait being studied. The F2 generation (second filial generation) refers to the offspring of the F1 generation, which can be either homozygous or heterozygous for the trait being studied.

10.2.d. Which molecule is responsible for transcription? What is a promoter and describe the role of promoters in transcription. Describe the process of transcription giving an example of the DNA template sequence of bases, and the resulting base sequence on the resulting transcript

A promoter is a region of DNA that initiates transcription of a particular gene. It acts as a binding site for RNA polymerase and transcription factors, which are proteins that help RNA polymerase locate the promoter and initiate transcription. During transcription, RNA polymerase binds to the promoter region of DNA and unwinds the double helix. Then, it reads the sequence of the template DNA strand and uses it as a template to synthesize a new RNA molecule by adding complementary RNA nucleotides one by one in a 5' to 3' direction. The RNA molecule that is produced is complementary to the template strand of DNA and therefore identical in sequence to the non-template (coding) strand of DNA, with the exception that RNA contains uracil (U) in place of thymine (T). For example, if the template strand of DNA has the sequence 5'- TACGTCAGT -3', then the RNA molecule that is synthesized will have the complementary sequence 3'- AUGCAGUCA -5'. This is known as the primary transcript or pre-mRNA.

9.1.e. What is an allele? How do alleles form and what do they contribute to the gene pool of a population?

An allele is a variant form of a gene that codes for a specific trait. Each gene can have multiple alleles, which are located at the same position (locus) on homologous chromosomes. Alleles can differ in their DNA sequence, resulting in different traits or variations of a trait. Alleles form through mutations in the DNA sequence of a gene, which can arise spontaneously or as a result of environmental factors such as radiation or chemicals. Mutations can create new alleles or modify existing ones, and these changes can be passed on to future generations through inheritance. Alleles contribute to the gene pool of a population, which is the total collection of genes and their alleles in a particular population. The frequency of different alleles in a population can change over time due to factors such as mutation, gene flow, genetic drift, natural selection, and sexual selection. These changes can affect the genetic diversity of a population and influence its ability to adapt to changing environments. The study of allele frequencies and their changes over time is an important aspect of population genetics.

.9.1.g. How is an understanding of Mendel's Law of Segregation relevant to drawing a punnet squareA man has a widow's peak, he is heterozygous for this trait. His wife has a straight hairline she is homozygous recessive for the trait. What do the letters on the outside of the box represent? What to the letters in the squares represent? What do the resulting numbers mean?

An understanding of Mendel's Law of Segregation is relevant to drawing a Punnett Square because it explains how alleles separate during gamete formation and how they combine during fertilization. The Law of Segregation states that each individual has two alleles for each trait, and these alleles separate during gamete formation so that each gamete only carries one allele for each trait. To solve the problem given, we first need to identify the alleles for each parent. The man is heterozygous for the trait, so he has one dominant "W" allele and one recessive "w" allele. His wife is homozygous recessive for the trait, so she has two recessive "w" alleles. The resulting numbers in the Punnett Square represent the probability of each genotype occurring in the offspring. In this case, we can see that there is a 50% chance of the offspring inheriting a heterozygous genotype (Ww) and a 50% chance of inheriting a homozygous recessive genotype (ww). Therefore, in this particular cross, the expected ratio of offspring with a widow's peak (Ww) to those with a straight hairline (ww) is 1:1.

9.1.k. How does the pattern of inheritance of an autosomal recessive trait differ from pattern of inheritance of an autosomal dominant trait? Provide named examples of an autosomal recessive condition and an autosomal dominant condition

Autosomal recessive inheritance requires two copies of the recessive allele to be present in order for the trait to be expressed, while autosomal dominant inheritance only requires one copy of the dominant allele to be present. Autosomal recessive traits tend to skip generations in families, while autosomal dominant traits do not. Individuals with autosomal recessive traits typically have unaffected parents, while individuals with autosomal dominant traits often have affected parents. An example of an autosomal recessive condition is cystic fibrosis, which is caused by mutations in the CFTR gene. Individuals with cystic fibrosis have two copies of the mutated gene, one inherited from each parent. Symptoms of cystic fibrosis include respiratory and digestive problems. An example of an autosomal dominant condition is Huntington's disease, which is caused by a mutation in the HTT gene. Individuals with Huntington's disease only need one copy of the mutated gene to develop the condition. Symptoms of Huntington's disease include neurological problems such as uncontrolled movements and cognitive decline.

.10.1.b. What do the letters RNA stand for? Compare and contrast DNA and RNA.

DNA and RNA are both types of nucleic acids that are essential for life and are involved in genetic information storage and expression. However, there are several key differences between the two: Structure: DNA has a double-stranded helical structure, while RNA usually exists as a single-stranded molecule. Sugar: DNA contains the sugar deoxyribose, while RNA contains the sugar ribose. Bases: DNA contains the nitrogenous bases adenine (A), guanine (G), cytosine (C), and thymine (T), while RNA contains the bases A, G, C, and uracil (U). Function: DNA is responsible for storing and transmitting genetic information, while RNA is involved in gene expression and protein synthesis. Overall, while DNA is like the "master blueprint" of an organism, RNA is like a "worker" that carries out the instructions specified by DNA.

10.1.a. What do the letters DNA stand for? What are the three components of a DNA nucleotide? Name the four nitrogen-containing bases of DNA and identify the complementary base pairs of DNA

DNA stands for Deoxyribonucleic acid. The three components of a DNA nucleotide are a sugar molecule (deoxyribose), a phosphate group, and a nitrogen-containing base. The four nitrogen-containing bases of DNA are adenine (A), thymine (T), guanine (G), and cytosine (C). The complementary base pairs of DNA are A-T and C-G, which means that adenine always pairs with thymine, and cytosine always pairs with guanine.

List the structures through which sperm cells would have to pass during an ejaculation.

During ejaculation, sperm cells pass through the following structures: Epididymis - where sperm cells mature and are stored Vas deferens - a tube that carries sperm from the epididymis to the urethra Ejaculatory duct - a short tube that merges the vas deferens with the urethra Urethra - a tube that carries both urine and semen out of the body Penis - the male organ that delivers semen to the female reproductive tract during sexual intercourse. The semen, which contains sperm cells and other fluids, is expelled from the body through the urethra during ejaculation.

23.4.c. Diagram and describe the muscular movements that are involved in inspiration to those involves in expiration. Describe how each set of muscular movement results in changes in pressure inside the thoracic cavity

During inspiration, the diaphragm contracts and moves downwards, while the external intercostal muscles contract and lift the ribcage upwards and outwards. These actions increase the volume of the thoracic cavity, which decreases the pressure inside the lungs, allowing air to flow in. During expiration, the diaphragm relaxes and moves upwards, while the external intercostal muscles relax and allow the ribcage to return to its resting position. Additionally, during forced expiration, the internal intercostal muscles contract and pull the ribcage downward and inward, further decreasing the volume of the thoracic cavity. These actions decrease the volume of the thoracic cavity, which increases the pressure inside the lungs, allowing air to flow out. Overall, these muscular movements work together to control the volume and pressure inside the thoracic cavity, allowing for efficient exchange of gases in the lungs.

22.2.a. Describe the order of organs through which food passes in the digestive system after food leaves the mouth. Describe the structure and function of each organ

Esophagus , Stomach, Small intestine, Large intestine (colon), Rectum, Anus Each organ in the digestive system has a unique structure and function: Esophagus: The esophagus is a muscular tube lined with a mucous membrane that secretes mucus to lubricate food as it passes through. The esophagus is a muscular tube that connects the mouth to the stomach. It uses a series of muscular contractions, known as peristalsis, to move food from the mouth to the stomach. Stomach: The stomach has several layers of muscle and a thick lining of mucus that protects it from the acid it produces. It also contains specialized cells that produce enzymes to help break down proteins. The stomach is a muscular sac that mixes food with digestive juices and enzymes to break it down into a liquid consistency. The stomach has three main layers of muscles that help mix and move food, and it also produces acid to help break down proteins. Small intestine: The small intestine is lined with villi and microvilli, which greatly increase its surface area for absorption. It also contains specialized cells that produce enzymes to break down carbohydrates, proteins, and fats. The small intestine is a long, narrow tube that is divided into three sections - the duodenum, jejunum, and ileum. It is where most of the nutrients from food are absorbed into the bloodstream. The walls of the small intestine are covered with tiny finger-like projections called villi, which increase the surface area for absorption. Large intestine (colon): The large intestine is wider than the small intestine and has a smooth inner lining. It contains several types of bacteria that help break down undigested food particles. The large intestine is a wider tube that absorbs water and electrolytes from the remaining waste material after the small intestine has absorbed nutrients. It also contains bacteria that help break down any remaining food particles. Rectum: The rectum is a short section of the large intestine that stores waste material before it is eliminated from the body. The rectum is the final section of the large intestine, where waste material is stored before being eliminated from the body. Anus: The anus is an opening in the skin at the end of the digestive tract that is surrounded by two rings of muscle called sphincters. These muscles help control the elimination of waste material from the body. The anus is the opening at the end of the digestive tract through which waste material is eliminated from the body. Examples of conditions that can affect the digestive system include irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), and celiac disease.

8.2.b. Both genes and chromosomes are composed of DNA, describe the structure and function of both. What is the relationship between genes and chromosomes.

Genes are small pieces of DNA that contain instructions for making proteins or RNA molecules, while chromosomes are larger structures made of DNA and proteins that contain many genes. Genes are located on chromosomes, and each chromosome contains many genes. The number and arrangement of chromosomes and genes vary among different organisms. Overall, genes and chromosomes work together to determine an organism's traits and genetic makeup. The structure of a gene includes a promoter region, which controls the start of transcription, a coding region, which specifies the sequence of amino acids in a protein, and a terminator region, which signals the end of transcription The structure of a chromosome includes a centromere, which is the point where the two chromatids are joined, and telomeres, which are the protective caps on the ends of the chromosome. Chromosomes are organized in pairs in most cells, with one set inherited from each parent.

.8.3.b. What are homologous chromosomes? How many pairs of homologous chromosomes are in diploid cells? What happens to homologous chromosomes during meiosis?

Homologous chromosomes are a pair of chromosomes that have the same genes at the same loci, but may have different alleles for those genes. In other words, homologous chromosomes carry the same genetic information but can have variations in that information. There are 23 pairs of homologous chromosomes in diploid cells, and during meiosis, homologous chromosomes undergo pairing, crossing over, and separation to produce haploid daughter cells with unique genetic combinations.

.8.3.d. Describe the following types of cells; haploid, diploid, somatic, gamete. Provide examples of each. Organize the four terms into pairs and support your reasoning for your choices

Haploid cells have one set of chromosomes, meaning they have one copy of each chromosome. Haploid cells are denoted as "n" and are produced by meiosis. Examples of haploid cells include sperm and egg cells in animals, as well as pollen and ovules in plants. Diploid cells have two sets of chromosomes, meaning they have two copies of each chromosome, one from each parent. Diploid cells are denoted as "2n" and are produced by the fusion of haploid gametes during fertilization. Examples of diploid cells include most cells in the human body, such as skin cells and muscle cells. Somatic cells are any non-reproductive cells in an organism, meaning they are not involved in sexual reproduction. Somatic cells are always diploid and carry the genetic information of the organism. Examples of somatic cells include skin cells, liver cells, and nerve cells in animals. Gametes are reproductive cells that are involved in sexual reproduction. Gametes can be haploid or diploid, depending on the organism. In animals, gametes are haploid and are produced by meiosis. In plants, gametes are diploid and are produced by mitosis. Examples of gametes include sperm and egg cells in animals, as well as pollen and ovules in plants. Pairs: Haploid and Diploid: These terms are paired because they describe the number of sets of chromosomes in a cell. Haploid cells have one set of chromosomes, while diploid cells have two sets of chromosomes. Somatic and Gamete: These terms are paired because they describe different types of cells in an organism. Somatic cells are non-reproductive cells, while gametes are reproductive cells involved in sexual reproduction.

26.2.j. What is the ideal temperature for sperm production? Describe how the body regulates the temperature of spermatogenesis

Ideally, sperm production occurs at around 93.2ºF (34ºC). This is 5.4ºF (3ºC) below normal body temperature of 98.6ºF (37ºC ). The ideal temperature for sperm production is slightly lower than the body temperature, around 2-3°C lower. The body regulates the temperature of spermatogenesis through a process called thermoregulation. This process involves the contraction and relaxation of muscles in the scrotum that raise and lower the testicles to adjust the temperature. When the temperature is too high, the muscles contract to move the testicles closer to the body to warm them up, and when the temperature is too low, the muscles relax to move the testicles further away from the body to cool them down. This helps to maintain the optimal temperature for sperm production.

Draw and label the process of DNA replication. If one parental strand has the base sequence GATTACA what would the complementary sequence of bases (a) on the complementary parental strand? (b) on the complementary daughter strand copied from this template.

If one parental strand has the base sequence GATTACA, the complementary sequence of bases on the complementary parental strand would be CTAATGT

26.2.f. Describe the path taken by egg cells as they develop and leave the body (unfertilized).

In females, the egg cells or ova are produced in the ovaries, which are located on either side of the uterus. During each menstrual cycle, one egg is released from an ovary in a process called ovulation. Once the egg is released from the ovary, it enters the oviduct (also known as the fallopian tube), which is a muscular tube that connects the ovary to the uterus. The egg moves along the oviduct with the help of cilia and peristalsis, which are muscular contractions that move the egg towards the uterus. If the egg is fertilized by a sperm cell in the oviduct, it will continue to move towards the uterus where it will implant and develop into a fetus. However, if the egg is not fertilized, it will continue to move towards the uterus and eventually disintegrate and be expelled from the body during menstruation. In summary, the path taken by egg cells as they develop and leave the body (unfertilized) is: ovary -> oviduct -> uterus -> expelled from the body during menstruation.

9.1.i. What is independent assortment? During which phase of meiosis does it occur?How does independent assortment contribute to genetic variation among siblings? Which alleles would be on gametes produced by an individual heterozygous for the following traits; Widows peak where W is dominant for widows peak, and w is recessive for straight hairline and, where E is dominant for free earlobes and e denotes the recessive trait for attached earlobes.

Independent assortment refers to the random arrangement of homologous chromosome pairs during metaphase I of meiosis. This means that the way one pair of chromosomes lines up on the metaphase plate is independent of how any other pair of chromosomes lines up. Independent assortment contributes to genetic variation among siblings because it allows for different combinations of maternal and paternal chromosomes to be passed on to offspring. During independent assortment, the homologous pairs of chromosomes randomly align on the metaphase plate, and each chromosome has an equal chance of ending up on either side of the plate. This random assortment means that each gamete produced during meiosis has a unique combination of maternal and paternal chromosomes, which contributes to genetic diversity in the offspring. To determine the possible gametes produced by an individual heterozygous for both traits, you would use the principle of independent assortment. This individual would have the genotype WwEe. During metaphase I of meiosis, the W and w alleles on the homologous pair of chromosomes can line up on either side of the metaphase plate, and the same is true for the E and e alleles on the other homologous pair of chromosomes. The possible gametes produced by this individual would be WE, We, wE, and we, with each gamete having an equal probability of being produced.

26.3.a. Name and describe 5 different methods of contraception. Rank them from most effective to least effective at preventing pregnancy.

Intrauterine devices (IUDs): These are small, T-shaped devices that are inserted into the uterus by a healthcare provider. IUDs can be either hormonal or non-hormonal and can provide long-term protection against pregnancy (up to 5-10 years depending on the type). They are over 99% effective. Implants: A small, flexible rod is inserted under the skin of the upper arm by a healthcare provider. It releases hormones to prevent pregnancy and can provide protection for up to 3 years. It is also over 99% effective. Sterilization: A permanent method of contraception for both men and women. For men, this involves a vasectomy, which involves cutting and sealing the tubes that carry sperm from the testes to the penis. For women, this involves a tubal ligation, which involves blocking or sealing the fallopian tubes to prevent eggs from reaching the uterus. It is over 99% effective. Birth control pills: A daily pill that contains hormones to prevent ovulation. If taken correctly, it can be over 99% effective. However, it requires strict adherence to a daily schedule to be effective. Condoms: A barrier method of contraception that is placed over the penis or inserted into the vagina to prevent sperm from reaching the egg. It is approximately 85-98% effective, depending on correct and consistent use.

8.3.e. Where and when does meiosis take place in the human body for (a) females, and(b) males? In humans which sex chromosomes are possessed by males and females? In terms of genes and chromosomes what are the objectives of meiosis?

Meiosis is the process of cell division that produces haploid cells, which have half the number of chromosomes as the original cell. In females, meiosis happens in the ovaries and produces egg cells, while in males, meiosis happens in the testes and produces sperm cells. Females have two X chromosomes (XX) and males have one X and one Y chromosome (XY). The main objectives of meiosis are to create genetic diversity by producing haploid cells with different combinations of genetic information, and to reduce the number of chromosomes in the gametes for sexual reproduction. The unique combinations of genetic information produced during meiosis are important for the adaptation of organisms to changing environments, while the halving of the number of chromosomes is necessary for the fusion of gametes during fertilization.

26.2.k. Name and describe each of the three phases of the uterine cycle.Approximatzation is not achieved?ely which day does ovulation occur? Which structure is shed if fertili

Menstrual Phase: The first phase of the uterine cycle starts on the first day of menstruation and lasts for approximately 3-7 days. During this phase, the thickened uterine lining from the previous cycle is shed along with blood and other materials through the vagina. Proliferative Phase: This phase occurs from approximately day 6 to day 14 of the cycle, just before ovulation. During this phase, the uterus begins to thicken and rebuild its lining, and the cervix produces more fertile cervical mucus to allow sperm to travel more easily through the reproductive tract. Secretory Phase: This phase occurs from approximately day 15 to day 28 of the cycle, after ovulation. During this phase, the uterus continues to thicken and the glands in the uterine lining secrete nutrients to nourish a potential embryo. If fertilization does not occur, the uterus will prepare to shed the lining again in the next menstrual phase. Ovulation typically occurs on day 14 of a 28-day cycle, although this can vary depending on the individual. If fertilization does occur, the fertilized egg will implant in the uterine lining and begin to grow into an embryo. If fertilization does not occur, the uterus will shed its lining during the next menstrual phase.

22.3.e. Provide a definition for a mineral? Why must our diet contain minerals? Name and describe the functions of 3 minerals

Minerals are naturally occurring inorganic substances that are essential for various body functions. Our diet must contain minerals as our body cannot produce them on its own. Calcium - Calcium is necessary for strong bones and teeth, blood clotting, nerve function, and muscle contraction. Iron - Iron is essential for the formation of hemoglobin, which carries oxygen in the blood. It also supports the immune system and helps to produce energy. Zinc - Zinc is required for proper growth and development, immune system function, wound healing, and DNA synthesis. It is also important for taste and smell perception

8.3.k. Compare and contrast mitosis and meiosis

Mitosis and meiosis are two different types of cell division that produce daughter cells with different genetic material and serve different purposes. Purpose: Mitosis is used for growth, repair, and asexual reproduction, while meiosis is used for sexual reproduction to generate genetic diversity. Number of divisions: Mitosis involves one division, while meiosis involves two divisions. Number of daughter cells: Mitosis produces two identical daughter cells, while meiosis produces four genetically diverse daughter cells. Genetic material: Mitosis produces daughter cells with the same number and type of chromosomes as the parent cell, while meiosis reduces the number of chromosomes by half and creates new combinations of genetic information. Stages: Mitosis has four stages (prophase, metaphase, anaphase, and telophase), while meiosis has eight stages (meiosis I and meiosis II, each with prophase, metaphase, anaphase, and telophase). Role in evolution: Meiosis contributes to genetic diversity, allowing for adaptation and evolution over time, while mitosis maintains the genetic status quo.

8.3.g. Name and contrast the 2 different forms of cell division. Identify one of the properties of life that is due to each type of cell division, and explain why that form of cell division is best suited to each property of life you chose.

Mitosis is a type of cell division that produces two identical daughter cells with the same number of chromosomes as the parent cell. Mitosis is used for growth, repair, and asexual reproduction in unicellular organisms. Mitosis is well-suited to the property of life known as homeostasis, which is the maintenance of a stable internal environment despite external changes. This is because mitosis ensures that each daughter cell has the same genetic material as the parent cell, which helps to maintain the organism's internal environment and keep it stable. Meiosis is a type of cell division that produces four genetically unique daughter cells with half the number of chromosomes as the parent cell. Meiosis is used for sexual reproduction in which the genetic material from two parent cells combines to produce an offspring with unique genetic traits. Meiosis is well-suited to the property of life known as adaptation, which is the ability of organisms to change and evolve over time to better survive in their environment. This is because meiosis generates genetic variation by creating unique combinations of genetic information, allowing organisms to adapt to changing environments over time. In summary, mitosis is best suited to the property of life known as homeostasis, which helps to maintain a stable internal environment, while meiosis is best suited to the property of life known as adaptation, which allows organisms to change and evolve over time to better survive in their environment.

8.2.d. Describe the events that occur during each of the 4 phases of mitosis. List them in the order in which they occur. What happens during cytokinesis? Contrast cytokinesis in animal and plant cells.

Mitosis is the process by which eukaryotic cells divide their genetic material into two identical daughter cells. It consists of four phases, which occur in the following order: Prophase: During prophase, chromatin condenses into discrete chromosomes. The nucleolus disappears, and the nuclear envelope breaks down. The spindle fibers, made of microtubules, begin to form at the centrosome. Metaphase: In metaphase, the chromosomes line up along the metaphase plate, an imaginary line in the center of the cell. The spindle fibers attach to the centromeres of each chromosome. Anaphase: In anaphase, the sister chromatids separate at the centromere and are pulled towards opposite poles of the cell by the spindle fibers. Telophase: During telophase, the chromosomes reach the opposite poles of the cell, and the spindle fibers disassemble. A new nuclear envelope forms around each set of chromosomes, and the chromosomes begin to decondense back into chromatin. Cytokinesis is the final stage of the cell cycle, during which the cell physically divides into two daughter cells. In animal cells, a contractile ring made of actin and myosin filaments forms around the cell and contracts, pinching the cell membrane and creating a cleavage furrow. This process continues until the membrane fuses in the center, dividing the cell into two daughter cells. cytokinesis in plant cells involves the formation of a cell plate, which is a new cell wall that forms between the two daughter cells. This cell plate is made of vesicles containing cell wall material and grows outward until it fuses with the existing cell wall, separating the two daughter cells.

23.4.b. Starting with the nose, list, in correct sequence, and describe the structures through which air passes in the human respiratory system during inhalation.

Nose: The nose is the primary external opening for the respiratory system. It filters and humidifies the air as it enters the body. Nasal cavity: The nasal cavity is a large air-filled space behind the nose. It is lined with mucous membranes, which filter and moisten the air. Pharynx: The pharynx, or throat, is a muscular tube that connects the nasal cavity and mouth to the larynx. It serves as a passageway for both air and food. Larynx: The larynx, or voice box, is located at the top of the trachea. It contains the vocal cords, which vibrate to produce sound. Trachea: The trachea, or windpipe, is a tube that connects the larynx to the bronchi. It is lined with cilia, which help to filter and move mucus out of the lungs. Bronchi: The bronchi are two large tubes that branch off from the trachea and enter each lung. They divide into smaller and smaller branches, eventually forming bronchioles. Bronchioles: Bronchioles are smaller branches of the bronchi that lead to the alveoli. Alveoli: Alveoli are small sacs within the lungs where gas exchange occurs. Oxygen enters the bloodstream and carbon dioxide is removed. During inhalation, the diaphragm contracts and flattens, and the intercostal muscles between the ribs contract, which increases the volume of the chest cavity. This decrease in pressure allows air to flow into the lungs through the structures listed above.

Complete the following table providing information on the role of the following structures in the female reproductive system; ovaries, oviducts, uterus, cervix, vagina

Ovaries: The ovaries are the female gonads responsible for producing eggs and female sex hormones, such as estrogen and progesterone. Each ovary contains thousands of follicles, which are small sacs that house developing eggs. Oviducts (fallopian tubes): The oviducts are a pair of muscular tubes that connect the ovaries to the uterus. They provide a pathway for the egg to travel from the ovary to the uterus. The oviducts are lined with cilia, which help move the egg along and also provide an environment for fertilization to occur. Uterus: The uterus is a muscular organ that is responsible for nurturing and supporting a developing embryo/fetus during pregnancy. The lining of the uterus, called the endometrium, thickens and becomes enriched with blood vessels in preparation for a fertilized egg to implant and grow. Cervix: The cervix is the lower part of the uterus that connects to the vagina. It acts as a barrier between the uterus and the outside world, and also helps keep sperm inside the reproductive tract during intercourse. During labor, the cervix dilates and opens up to allow the baby to pass through. Vagina: The vagina is a muscular tube that connects the cervix to the outside of the body. It is the passageway for menstrual flow and for intercourse, and also serves as the birth canal during delivery. The walls of the vagina are lined with mucus-secreting glands that help keep it moist and lubricated.

2.1.b. What are plasmids? Which cells naturally contain plasmids? Describe their role in their natural cells. Describe the role of plasmids in genetic engineering. What are the limitations of using plasmids in biotechnology?

Plasmids are small, circular DNA molecules found in some bacterial and archaeal cells. They are separate from the chromosomal DNA and can replicate independently. Plasmids can carry non-essential genes that provide benefits to the host cell, such as antibiotic resistance or the ability to produce toxins. In genetic engineering, plasmids are used as vectors to introduce foreign DNA into host cells. Scientists can insert a gene of interest into a plasmid and then introduce the plasmid into a bacterial or yeast cell. The host cell can then replicate the plasmid along with its own DNA, producing large amounts of the gene product. However, there are limitations to using plasmids in biotechnology. Plasmids have a limited carrying capacity, so only relatively small pieces of DNA can be inserted. Additionally, plasmids can be unstable and easily lost during cell division, leading to inconsistent gene expression. Finally, the use of plasmids in genetically modified organisms raises ethical and safety concerns.

What are restriction enzymes? Describe their natural role in the cells in which they were first found. Diagram how restriction enzymes cut, DNA which term is used to describe this type of cut, and which bonds are broken by restriction enzymes?

Restriction enzymes, also known as restriction endonucleases, are enzymes that can cut DNA at specific sequences of nucleotides. They are naturally found in bacteria, where they play a role in protecting the bacteria from invading viruses by cutting up viral DNA. When a restriction enzyme recognizes a specific sequence of nucleotides, it binds to that sequence and cuts the DNA strand at a particular point. The resulting cut is referred to as a "restriction site" or "restriction site cut". Restriction enzymes cut the sugar-phosphate backbone of the DNA molecule, specifically the phosphodiester bonds between nucleotides. Below is an example of how a restriction enzyme might cut a DNA molecule: Original DNA sequence: AATTGGCC Restriction enzyme recognition sequence: AACGTT Cut DNA sequence: AATTG | GCC Note that the cut occurs between the G and C nucleotides, leaving "sticky ends" or "overhangs" on each side of the cut. These sticky ends can be used to join DNA fragments together in genetic engineering techniques such as DNA cloning.

26.2.h. Describe the path taken by sperm cells in order to fertilize an egg.(Where does fertilization take place?)..

Sperm cells are produced in the testes and are transported through the epididymis, vas deferens, and ejaculatory duct into the urethra. During sexual intercourse, the sperm are ejaculated from the urethra into the vagina. They then travel through the cervix and into the uterus, and then into the oviducts (also known as fallopian tubes), which are the site of fertilization. The sperm must successfully swim through the female reproductive tract to reach the egg and fertilize it in the oviduct

26.2.a. Complete the following table providing information on the function of the following organs and glands of the male reproductive system; testes, vas deferens ,seminal vesicles, prostate gland, bulbourethral gland ,testes

Testes: The testes are the primary male reproductive organs responsible for producing sperm and male hormones such as testosterone. Vas deferens: The vas deferens is a tube that carries sperm from the testes to the urethra. Seminal vesicles: The seminal vesicles are two small glands located near the prostate gland that produce a fluid that mixes with sperm to form semen. Prostate gland: The prostate gland is a small gland located below the bladder that produces a fluid that helps nourish and protect sperm. Bulbourethral gland: The bulbourethral gland, also known as Cowper's gland, is a small gland located below the prostate gland that produces a fluid that lubricates the urethra and neutralizes any acidic urine remaining in the urethra before ejaculation. Testes: The testes are responsible for producing sperm and male hormones such as testosterone.

.8.2.c. What is the cell cycle? List the four stages of the cell cycle in the correct order.Describe the phases of the cell cycle and explain what occurs in each. During which phase of the cell cycle is DNA replicated?

The cell cycle refers to the series of events that occur in a cell as it grows and divides into two daughter cells. The cell cycle consists of four stages in the following order: G1 phase: The cell grows and carries out normal metabolic activities. S phase: DNA replication occurs in this stage, and the chromosomes are duplicated. G2 phase: The cell prepares for division by making more organelles and proteins. M phase: The cell divides into two daughter cells through mitosis (in eukaryotes) or binary fission (in prokaryotes). The four stages of the cell cycle are G1, S, G2, and M, and DNA replication occurs during the S phase.

12.1.d. Draw and describe four steps involved in creating a molecule of recombinant DNA. Provide a named example of a commercial product made using recombinant DNA

The following are the four steps involved in creating a molecule of recombinant DNA: Isolation of DNA: The first step in creating recombinant DNA is to isolate DNA from the donor organism and the recipient organism. Cutting of DNA: In the second step, restriction enzymes are used to cut the DNA of both organisms at specific sites. This results in the creation of sticky ends, which are single-stranded overhangs. Joining of DNA: The third step involves the joining of the cut DNA fragments of the donor and recipient organisms using DNA ligase. The sticky ends of the donor DNA bind to the complementary sticky ends of the recipient DNA. Introduction of recombinant DNA: In the final step, the recombinant DNA molecule is introduced into the recipient organism. This can be done using various methods, such as transformation or electroporation. An example of a commercial product made using recombinant DNA technology is insulin. Recombinant DNA technology has allowed for the production of human insulin using bacteria, which has replaced the use of insulin derived from animal sources.

.12.2.a. What is the goal of Polymerase Chain Reaction (PCR)? Describe the process ofPCR. Provide 2 examples of an application of PCR.

The goal of Polymerase Chain Reaction (PCR) is to amplify a specific DNA sequence from a small amount of starting material. The process of PCR involves several steps: Denaturation: The double-stranded DNA template is heated to a high temperature (around 95°C) to separate the strands. Annealing: The temperature is lowered to allow the primers (short pieces of DNA that are complementary to the template DNA) to anneal to the single-stranded DNA template at specific locations flanking the target sequence. Extension: DNA polymerase, along with free nucleotides, extends the primers by synthesizing new DNA strands, using the template as a guide. Repeat: The cycle of denaturation, annealing, and extension is repeated for several rounds, doubling the amount of DNA with each cycle. Two examples of applications of PCR are: Medical diagnosis: PCR can be used to detect the presence of pathogens (such as viruses or bacteria) in a patient's sample. The specific DNA sequence of the pathogen is amplified and detected, allowing for rapid and accurate diagnosis. Forensic analysis: PCR can be used to amplify DNA from a crime scene, even when only a small amount of DNA is present. The amplified DNA can then be analyzed to identify suspects or confirm identities.

8.3.a. Describe the human life cycle. Which processes of cell division are due to mitosis and which are accomplished by meiosis? Which cells are haploid and which cells are diploid?

The human life cycle begins with the fusion of a haploid sperm cell from the father and a haploid egg cell from the mother, resulting in a diploid zygote. The zygote then undergoes mitosis and cell differentiation to form an embryo, which develops into a fetus and eventually a newborn baby. After birth, the human life cycle includes growth and development, reproduction, and aging. mitosis is responsible for the division of somatic cells and produces two identical diploid daughter cells, while meiosis is responsible for the production of haploid gametes for sexual reproduction and results in four genetically diverse daughter cells. diploid-mitosis haploid-meiosis

2.2.l. Describe the difference in structure and function between the small intestine and the large intestine..

The small intestine is a long, narrow tube that is part of the digestive system, located between the stomach and the large intestine. It is the primary site of nutrient absorption in the digestive system. The inner surface of the small intestine is lined with tiny, finger-like projections called villi, which greatly increase the surface area available for absorption. The large intestine, on the other hand, is wider and shorter than the small intestine, and is the final part of the digestive system. Its main function is to absorb water from undigested food, and to eliminate solid waste from the body. Unlike the small intestine, the large intestine does not have villi. Instead, its inner surface has many small, finger-like projections called microvilli, which help absorb water and nutrients. Overall, the small intestine is specialized for nutrient absorption, while the large intestine is specialized for water absorption and waste elimination.

.22.2.e. Name and describe the three functions of the stomach. Explain why you can eat and digest tripe (basically an animals stomach), but you do not digest your own stomach lining

The stomach is a muscular sac-like organ located between the esophagus and small intestine. It performs three main functions: Storage: The stomach stores food that has been swallowed until it can be further digested in the small intestine. Mechanical digestion: The stomach churns and mixes the food with gastric juices to break it down into smaller pieces. Chemical digestion: The stomach produces gastric juice, which contains hydrochloric acid and enzymes, that break down proteins and other macromolecules in food. Tripe, which is the stomach lining of an animal, can be eaten and digested because the digestive enzymes in our stomach are capable of breaking down the proteins and other macromolecules in the stomach lining. However, the lining of our own stomach is protected by a layer of mucus, which prevents our digestive enzymes from digesting it. Additionally, the cells in our stomach lining have a rapid turnover rate, meaning they are constantly being replaced, allowing for the maintenance of a healthy stomach lining.

.22.2.h. What two major functions of the digestive system are carried out in the small intestine. What structural features of the small intestine increase the surface area of the small intestine?

The two major functions of the digestive system carried out in the small intestine are the absorption of nutrients and the complete digestion of food. The small intestine has structural features that increase its surface area to enhance its function. The inner lining of the small intestine is covered with tiny finger-like projections called villi, and these villi are covered with even smaller projections called microvilli. Together, these structures increase the surface area of the small intestine, allowing for more efficient absorption of nutrients. The walls of the small intestine are also lined with specialized cells that secrete digestive enzymes and other substances that aid in digestion and nutrient absorption.

22.3.c. How many amino acids are used by the body to build proteins? How many are' essential amino acids'? Provide examples of complete and incomplete sources of proteins. How can vegans obtain all necessary amino acids? Provide an example of a vegan meal that contains all of the amino acids.

There are 20 different amino acids that are used by the body to build proteins. Out of these 20 amino acids, 9 are considered essential amino acids, which means that they cannot be produced by the body and must be obtained through the diet. Examples of complete protein sources include meat, poultry, fish, eggs, and dairy products, which contain all 9 essential amino acids. Incomplete protein sources are those that lack one or more essential amino acids, such as grains, beans, nuts, and vegetables. Vegans can obtain all necessary amino acids by consuming a variety of plant-based protein sources throughout the day. Combining complementary protein sources can ensure that all essential amino acids are obtained. For example, combining beans and rice or hummus and pita bread can provide all 9 essential amino acids. Other examples of vegan meals that contain all of the amino acids include quinoa and roasted vegetables, lentil soup with whole grain bread, or a tofu stir-fry with brown rice and vegetables.

22.3.j. Describe the synthesis of vitamin D in the human body. Provide two examples of dietary sources of Vitamin D. Describe the function of Vitamin D in the human body, and what happens if there is a deficiency of Vitamin D?

Vitamin D is synthesized in the human body when the skin is exposed to sunlight. Specifically, when ultraviolet B (UVB) radiation penetrates the skin, it triggers the conversion of a cholesterol precursor molecule into vitamin D3. This molecule then travels to the liver and kidneys, where it is further modified into its active form, calcitriol. Dietary sources of Vitamin D include fatty fish (such as salmon, tuna, and mackerel), egg yolks, and fortified foods (such as milk and cereal). The function of Vitamin D in the human body is to help regulate calcium and phosphorus absorption, which are essential minerals for healthy bones and teeth. Additionally, Vitamin D has been found to play a role in immune function, muscle function, and reducing inflammation. A deficiency of Vitamin D can lead to a variety of health problems, including weakened bones (osteoporosis), increased risk of fractures, and rickets (a disease that causes softening and weakening of bones in children). Additionally, recent research has suggested that Vitamin D deficiency may be linked to other health conditions, such as certain cancers, heart disease, and autoimmune disorders.

22.3.d. Provide a definition for a vitamin? Why must our diet contain vitamins? Name and describe the functions of 3 vitamins

Vitamins are organic compounds that are essential for the normal growth, development, and maintenance of the human body. Our body cannot produce most of these vitamins, so we need to obtain them through our diet. Vitamin A: Helps maintain healthy vision, skin, and immune system. It also plays a role in bone growth and reproductive health. Sources include liver, carrots, sweet potatoes, and spinach. Vitamin C: Helps with the growth and repair of tissues throughout the body, and is important for the immune system. It also helps the body absorb iron. Sources include citrus fruits, strawberries, kiwi, and broccoli. Vitamin D: Helps the body absorb calcium and is important for bone health. It also plays a role in the immune system and muscle function. Our body can make vitamin D when exposed to sunlight, and it is also found in fatty fish, egg yolks, and fortified dairy products.

22.2.d. Describe how food is moved from your throat to your stomach. What functions of the digestive system are carried out in your stomach? What is the composition of the digestive juices found in the stomach?

When you swallow food, it travels down the esophagus through a process called peristalsis, which involves the contraction and relaxation of muscles that push the food down. At the end of the esophagus, there is a ring-like muscle called the lower esophageal sphincter (LES) that opens up to allow food into the stomach and then closes to prevent stomach contents from flowing back up into the esophagus. In the stomach, food is mixed with digestive juices containing hydrochloric acid and enzymes, which break down proteins and kill any harmful bacteria that may be present. The stomach also churns the food, mixing it with the digestive juices and turning it into a liquid-like substance called chyme. The three functions of the stomach are: Storage: The stomach can stretch to hold large amounts of food and slowly release it into the small intestine for further digestion and absorption. Mechanical digestion: The stomach churns the food and mixes it with digestive juices, breaking it down into smaller pieces. Chemical digestion: The digestive juices in the stomach contain enzymes that break down proteins into smaller peptides and amino acids.

9.1.f. What do the terms 'recessive' and 'dominant' mean? What convention is followed to describe between dominant and recessive alleles in text? What determines if an allele is recessive or dominant? Under which circumstances are recessive alleles expressed?Use an example to support your answer

Whether an allele is recessive or dominant is determined by its effect on the phenotype of an organism. A dominant allele expresses its trait even in the presence of a different allele, while a recessive allele only expresses its trait when two copies of that allele are present. For example, in humans, the gene for hairline shape has two alleles: the dominant "W" allele for a widow's peak hairline, and the recessive "w" allele for a straight hairline. If an individual has two copies of the dominant "W" allele or one "W" and one "w" allele, they will have a widow's peak hairline. However, if an individual has two copies of the recessive "w" allele, they will have a straight hairline. Recessive alleles are only expressed in individuals who inherit two copies of the same recessive allele, one from each parent. This is because in heterozygous individuals (with one dominant and one recessive allele), the dominant allele masks the expression of the recessive allele. The expression of recessive alleles is important for genetic diversity, as they can remain hidden in a population for generations until two carriers of the recessive allele produce offspring with two copies of the allele.

Compare and contrast asexual and sexual reproduction, provide examples of each.Provide examples of organisms that (a) only reproduce asexually, and (b) only reproduce sexually. Discuss the advantages and disadvantages of each

While asexual reproduction only involves one organism, sexual reproduction requires both a male and a female. Some plants and unicellular organisms reproduce asexually. Most mammals and fish use sexual reproduction. Some organisms like corals and komodo dragons can reproduce either sexually or asexually. Aesexual rep- eliminates mate need, no genetic varaibility, clones, no adaptation- env may change and species may not survivie Sexual rep- genetic variability Asexual ex: flowers, plants, fungi, sea stars sexual ex: humans, mammals, fish, birds

sexual reproduction

type of reproduction in which cells from two parents unite to form the first cell of a new organism fusion of two hapliod(n) sex cells called gametes(sperm and egg) and the formation of a diploid(2n) zygote