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Questions and Answers
What is the sugar molecule found in DNA?
What is the function of promoters in DNA?
What is the main difference between DNA and RNA?
What is the function of histones in eukaryotic cells?
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What is the name of the segments of DNA that can move throughout the genome?
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What is the main purpose of meiosis?
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What is the term for the process of an egg and a sperm combining their genetic material?
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What is the result of crossing-over during meiosis I?
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What is the number of cell divisions involved in meiosis?
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What is the term for the type of cell division that results in two identical diploid cells?
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What is the primary function of DNA in eukaryotic cells?
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What is the role of lactase in the human body?
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What is the result of a damaged p53 protein?
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What is the function of hemoglobin in the human body?
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What is the purpose of cell differentiation?
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What is the process by which undifferentiated cells become specialized cells with a specific structure and function?
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What is the main reason why somatic cells look and behave differently from each other despite having the same genome?
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What is the role of transcription factors in cell differentiation?
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What is the purpose of differential gene expression analysis in the study of cellular differentiation?
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What is the function of enhancers and promoters in gene expression?
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Study Notes
Genetic Material
- Genetic material is the hereditary material of the cell, holding the information needed for all cell structure and function.
- There are two main types of genetic material: DNA and RNA.
- In eukaryotic cells, DNA is stored in the nucleus, wrapped around proteins called histones.
- In prokaryotic cells, DNA exists in the cytoplasm.
DNA Structure
- DNA is a double helix made of two strands of nucleotides twisted together.
- Each nucleotide consists of a sugar, a phosphate, and a base.
- There are four bases in DNA: adenine (A), guanine (G), cytosine (C), and thymine (T).
RNA
- RNA is made of nucleotides but has ribose sugar instead of deoxyribose.
- RNA is single-stranded, and different bases are used, including adenine (A), guanine (G), cytosine (C), and uracil (U).
Human Genome
- The human genome is made up of many different types of DNA sequences, including:
- Introns (intervening sequences)
- Exons (expressed regions that encode amino acids)
- Unique noncoding DNA (pseudogenes, segments of inactive DNA)
- Regulatory sequences (promoters, which delineate where gene transcription begins)
- Repetitive DNA (sequences repeated throughout the genome, related to transposable elements)
Protein Synthesis
- Deoxyribonucleic acid (DNA) is a double helix structure composed of nucleotides.
- Nucleotides are composed of a phosphate group, a deoxyribose sugar, and a nitrogen-containing base.
- Nitrogen-containing bases form hydrogen bonds to form the double helix.
- DNA resides in the nucleus of eukaryotic cells or floats freely in the cytoplasm of prokaryotic cells.
- DNA provides instructions for protein synthesis through transcription and translation.
Protein Functions
- Proteins serve many functions in the cell, including:
- Providing structure
- Regulating body processes
- Transporting materials
- Balancing fluids
- Helping with immunity
- Providing energy
- Examples of proteins include:
- Keratin (found in hair and skin)
- Collagen (found in connective tissues)
- Hormones (regulate body processes and cell activity)
- Enzymes (speed up chemical processes)
- Hemoglobin (transports oxygen from the lungs)
Cell Division
- Cell division is essential in all living organisms.
- In eukaryotes, cell division occurs via:
- Mitosis (produces new somatic, or body, cells)
- Meiosis (produces gametes, like sperm and ova)
- Mitosis has five stages:
- Prophase (chromosome condensation, break-down of nuclear envelope)
- Metaphase (chromosomes aligned at metaphase plate)
- Anaphase (sister chromatids pulled to each end of the cell)
- Telophase (nuclear envelope forms again)
- Cytokinesis (cleavage furrow separates daughter cells in animal cells, cell plate separates daughter cells in plant cells)
Cell Differentiation
- Cell differentiation is the process of stem cells becoming more specialized.
- Cell differentiation creates diversity in life on Earth, within the cells of our body, and allows cells to create unique structures that fit their individualized functions.
Somatic Cells
- Somatic cells are specialized cells with a fixed structure and function.
- Examples of somatic cells include liver cells, skin cells, kidney cells, and brain cells.
- Before somatic cells became specialized, they were undifferentiated cells called stem cells in the fetus.
- Cellular differentiation is the process that triggers cellular differentiation, and it is triggered by differential gene expression.
Genes
- Genes are the basic unit of inheritance, composed of DNA.
- Genes reside in the nucleus of eukaryotic cells, wrapped around proteins called histones.
- In prokaryotes, genes are present on chromosomes floating free in the cytoplasm.
- Gene expression into proteins is guided by extrinsic factors such as enhancers and promoters.
Chromosomes
- Chromosomes are structures containing DNA wrapped around histones to form nucleosomes.
- There are 46 human chromosomes, forming 22 pairs of autosomal chromosomes and one pair of sex chromosomes.
- Chromosomes represent a pair of sister chromatids, each containing the same genetic information, joined by a common centromere.
- There are four main types of chromosomes:
- Metacentric chromosomes (centromere located at the center)
- Submetacentric chromosomes (centromere slightly off-center)
- Acrocentric chromosomes (centromere significantly off-center)
- Telocentric chromosomes (centromere located at the end of the chromosome)
Meiosis
- Meiosis is a process in which a gamete-producing cell undergoes two cell divisions, known as meiosis I and meiosis II, to produce four gametes (sperm or egg cells).
- Meiosis allows for genetic variations in offspring during sexual reproduction.
- Meiosis has two main divisions: meiosis I and meiosis II.
- During meiosis I, homologous pairs of chromosomes combine to form a tetrad, and chromatids exchange alleles, resulting in genetically unique allele combinations.
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Description
This quiz covers the basics of genetic material, including DNA and RNA, their storage in eukaryotic and prokaryotic cells, and the structure of DNA as a double helix.
