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SCIENCE test review sick humans
Unit 2: Genetics, Cell Cycle, and Cancer Review Sheet
Proteins/Enzyme:
Amino Acids:
The building blocks of proteins.
There are 20 different amino acids that combine in various sequences to form proteins.
Proteins:
Long chains of amino acids that fold into specific shapes.
Proteins are responsible for many functions in the body, including enzyme activity, cell signaling, and structural support.
Shape/Function of Proteins:
The shape of a protein is crucial to its function.
If the shape is altered, the protein may no longer function properly (e.g., sickle cell anemia, where a mutation changes the shape of hemoglobin, affecting its function).
What happens if you change the shape of a protein:
A protein's function can be disrupted if its shape is altered, potentially leading to diseases or dysfunction in the cell.
Function of an Enzyme:
Enzymes are proteins that act as catalysts, speeding up chemical reactions without being consumed.
They are essential in processes like digestion, metabolism, and DNA replication.
Why Enzymes Are Important:
They lower the activation energy needed for reactions to occur, making biological processes more efficient.
Without enzymes, many biological processes would occur too slowly to sustain life.
Evolution of Sick Humans Packet 1: Major Concepts
Heredity:
The passing of traits from parents to offspring through genes.
Allele:
Different versions of a gene. For example, a gene for eye color can have a brown allele or a blue allele.
Dominant Allele/Trait:
A dominant allele masks the expression of a recessive allele. If you inherit a dominant allele, that trait will be expressed.
Recessive Allele/Trait:
A recessive allele is only expressed when an individual has two copies of that allele (homozygous recessive).
Homozygous Dominant:
An individual with two identical dominant alleles (e.g., AA).
Homozygous Recessive:
An individual with two identical recessive alleles (e.g., aa).
Heterozygous:
An individual with one dominant and one recessive allele (e.g., Aa).
Genotype vs Phenotype:
Genotype: The genetic makeup of an individual (e.g., Aa, BB).
Phenotype: The physical expression of traits (e.g., brown eyes, tall).
Structure of DNA:
DNA is a double helix made up of nucleotides, which include a sugar, phosphate group, and a nitrogenous base (adenine, thymine, cytosine, guanine).
DNA Base Pair Rules:
Adenine (A) pairs with Thymine (T).
Cytosine (C) pairs with Guanine (G).
RNA Base Pair Rules:
Adenine (A) pairs with Uracil (U) (instead of Thymine).
Cytosine (C) pairs with Guanine (G).
Coding vs Non-coding DNA:
Coding DNA: Sequences that are transcribed into RNA and translated into proteins.
Non-coding DNA: DNA that does not code for proteins but may play roles in regulating gene expression.
How the Environment or Culture Influences Genes:
Environmental factors (like diet, exposure to toxins, or stress) can influence gene expression through epigenetics.
How Genes Are Inherited from Parent to Offspring:
Genes are inherited through the combination of alleles from each parent. A Punnett square can be used to predict the probability of inheriting certain traits.
Punnett Square:
A tool used to predict the genetic outcome of a cross between two organisms based on their genotypes.
Steps of DNA to RNA Transcription:
Initiation: RNA polymerase binds to the DNA at the promoter.
Elongation: RNA polymerase adds RNA nucleotides complementary to the DNA template.
Termination: The RNA polymerase reaches a termination signal, and the RNA is released.
Transcribing DNA to RNA:
For example, if the DNA sequence is 5’-ATGC-3’, the RNA sequence will be 5’-UACG-3’.
Translating Codons to Amino Acids:
Codons (3-letter sequences in RNA) are translated into amino acids using the genetic code chart.
For example, AUG = Methionine, UUU = Phenylalanine.
Lactose Intolerance and Persistence:
Lactose intolerance occurs when the body cannot properly digest lactose due to a lack of the enzyme lactase.
Lactase persistence is a genetic trait where individuals continue to produce lactase into adulthood.
Evolution of Sick Humans Packet 2: Major Concepts
Chromatin vs Chromosomes:
Chromatin: The uncoiled form of DNA found in the nucleus.
Chromosomes: Coiled and condensed chromatin during cell division.
Chromosome Number in a Normal Cell:
A normal human cell has 46 chromosomes (23 pairs).
Chromosome Number After S Phase:
After the S phase, each chromosome is replicated, but the total number of chromosomes remains 46; however, each chromosome consists of two sister chromatids.
Interphase:
The phase of the cell cycle before mitosis, consisting of:
G1 Phase: Cell growth.
S Phase: DNA replication.
G2 Phase: Preparation for mitosis.
Checkpoints:
Ensures that the cell cycle progresses correctly and repairs any issues before proceeding to the next phase.
Mitosis Steps:
Prophase: Chromosomes condense, nuclear membrane breaks down.
Metaphase: Chromosomes align at the center.
Anaphase: Sister chromatids are pulled apart.
Telophase: Nuclear membranes re-form.
Cytokinesis: Cytoplasm divides.
If a Cell Cycle Step Goes Wrong:
If errors occur (e.g., chromosomes don’t separate properly), it can lead to genetic disorders or cancer.
Cell Differentiation:
The process by which cells become specialized in structure and function.
Stem Cells:
Undifferentiated cells that can become any type of cell.
Why Cancer Occurs:
Cancer occurs when mutations in genes control cell division, leading to uncontrolled cell growth.
Where Are the Mistakes?:
Mistakes usually occur in genes regulating the cell cycle (e.g., tumor suppressor genes).
Why Are Mistakes an Issue in the Long Run?:
These mistakes can lead to uncontrolled cell division, resulting in tumors and cancer.
Mutations:
Substitution: One base is replaced by another.
Deletion: A base is removed.
Insertion: A base is added.
Mutations can lead to changes in proteins, possibly causing diseases.
Leukemia:
A type of cancer where the body produces abnormal white blood cells.
How it Occurs: Mutations lead to abnormal blood cell production.
Symptoms: Fatigue, frequent infections, bruising, etc.
Why Symptoms Occur: Abnormal blood cells cannot perform their normal function, leading to weakness and increased infection risk.
Be able to recognize or model:
Enzyme/Substrate Interaction: Enzyme binds to a substrate, forms an enzyme-substrate complex, and then catalyzes a reaction.
DNA Replication: The process where DNA is copied to ensure genetic information is passed on during cell division.
DNA to RNA Transcription: RNA polymerase synthesizes RNA based on a DNA template.
RNA to Amino Acid Translation: mRNA is translated by ribosomes to form a polypeptide chain (protein).
Cell Cycle (Interphase and Mitosis): Understand the stages and their purpose.
