bio final

What is a Punnett square?

A diagram used to predict the outcome of a genetic cross by showing the possible combinations of alleles from the parents.

What is a simple one trait cross?

A genetic cross that examines the inheritance of a single trait, typically involving one gene with two alleles.

What is a basic two trait cross?

A genetic cross that examines the inheritance of two traits simultaneously, often involving parents that are heterozygous for both traits.

What are sex-linked traits?

Traits that are associated with genes located on sex chromosomes, often affecting one sex more than the other, such as hemophilia and color blindness.

What is hemophilia?

A genetic disorder that impairs the body's ability to make blood clots, leading to excessive bleeding; it is often inherited in a sex-linked recessive pattern.

What is simple dominance?

A genetic scenario where the dominant allele completely masks the effect of the recessive allele in the phenotype.

What is incomplete dominance?

A genetic scenario where one allele does not completely mask the other, resulting in a blended phenotype.

What is codominance?

A genetic scenario where both alleles in a heterozygote are fully expressed, resulting in a phenotype that shows both traits.

What are multiple alleles?

A situation where three or more alleles exist for a particular gene.

What are polygenic traits?

Traits that are influenced by multiple genes, each contributing to the phenotype.

What is the difference between phenotype and genotype?

Phenotype refers to the observable characteristics of an organism, while genotype refers to the genetic makeup or alleles present.

What is a recessive trait?

A trait that is expressed only when two recessive alleles are present; it is masked by the presence of a dominant allele.

What is a carrier?

An individual who has one copy of a recessive allele for a trait but does not exhibit the trait themselves.

What is a test cross?

A genetic cross between an individual with an unknown genotype and a homozygous recessive individual to determine the unknown genotype.

What is an autosome?

Any chromosome that is not a sex chromosome.

What is the difference between autosomal dominant and autosomal recessive?

Autosomal dominant traits require only one copy of the dominant allele to be expressed, while autosomal recessive traits require two copies of the recessive allele.

What are some examples of genetic disorders?

Examples include cystic fibrosis, Huntington's disease, and hemophilia.

What is DNA?

Deoxyribonucleic acid; the molecule that carries genetic information for the development and functioning of an organism.

What is a gene?

A specific sequence of DNA that contains the instructions for making a protein or functional RNA molecule.

What is Mendel's law of segregation?

The principle stating that during the formation of gametes, the two alleles for a trait separate so that each gamete carries only one allele.

What is Mendel's law of independent assortment?

The principle stating that genes for different traits are inherited independently of one another during gamete formation.

What is homozygous?

An organism that has two identical alleles for a particular gene.

What is heterozygous?

An organism that has two different alleles for a particular gene.

What is a pedigree chart?

A chart or family tree that tracks which family members have a particular trait across several generations.

Why is human skin color considered a polygenic trait?

It is controlled by multiple genes, resulting in a wide range of phenotypic variations.

What is a zygote?

The diploid cell produced by the fusion of two haploid gametes.

What is selectively permeable?

A property of cell membranes that allows certain substances to pass while blocking others.

What is diffusion?

A passive transport process where molecules move from an area of high concentration to an area of low concentration without the use of energy.

What is osmosis?

The diffusion of water across a semipermeable membrane from a region of higher water concentration to a region of lower water concentration.

What is osmotic pressure?

The pressure that develops when water moves across a semipermeable membrane.

What is turgor pressure?

The hydrostatic pressure exerted by fluid within a cell against its cell wall.

What is plasmolysis?

The shrinking of a plant cell's cytoplasm away from its cell wall due to loss of water.

What is cytolysis?

The swelling of a cell that can lead to its rupture, typically due to excessive water intake.

What is hypertonic?

A solution that has a higher concentration of solutes compared to another solution.

What is hypotonic?

A solution that has a lower concentration of solutes compared to another solution.

What is isotonic?

A solution where the concentration of solutes is equal inside and outside the cell.

What is phagocytosis?

A type of endocytosis where a cell engulfs solid particles.

What is pinocytosis?

A type of endocytosis where a cell takes in fluid containing nutrients.

What is ATP?

Adenosine triphosphate, a molecule that stores and transfers energy within cells.

What is the purpose of photosynthesis?

To convert light energy into chemical energy stored in glucose.

What is the purpose of cellular respiration?

To convert biochemical energy from nutrients into ATP.

What is natural selection?

The process by which organisms better adapted to their environment tend to survive and produce more offspring.

What is reproductive isolation?

A condition that prevents different species from interbreeding, leading to speciation.

What is geographic isolation?

A form of reproductive isolation where physical barriers prevent populations from interbreeding, leading to speciation.

What is a codon?

A sequence of three nucleotides in mRNA that corresponds to a specific amino acid or stop signal during protein synthesis.

What is an anticodon?

A sequence of three nucleotides in tRNA that is complementary to a codon in mRNA, allowing for proper amino acid incorporation during translation.

What is a mutation?

A change in the DNA sequence that can lead to variations in traits, which may or may not affect an organism's phenotype.

What is endocytosis?

The process where cells take in material from the outside environment, which is a type of active transport.

What is exocytosis?

The process where a cell expels or moves materials out of the cell, requiring energy.

What is receptor-mediated endocytosis?

A type of active transport that requires specific receptors to allow substances, such as cholesterol, to enter the cell.

What is a solute?

The substance that is dissolved in a solution.

What is a solvent?

The substance that does the dissolving in a solution.

What is concentration?

The amount of solute that is dissolved in a given volume of solvent or solution.

What is facilitated diffusion?

A type of passive transport that allows substances to cross membranes with the help of transport proteins.

What is active transport?

The movement of substances across a cell membrane against their concentration gradient, requiring energy.

What is passive transport?

The movement of substances across a cell membrane without the use of energy.

What is crenation?

The process where a red blood cell shrinks due to loss of water in a hypertonic solution.

What are carrier proteins?

Membrane proteins that bind to specific substances and help move them across the membrane.

What are channel proteins?

Membrane proteins that form channels allowing specific substances to move across the membrane.

What are cell recognition proteins?

Proteins that help the immune system recognize when the body is being invaded by pathogens.

What are receptor proteins?

Proteins that have a specific shape allowing them to bind with specific molecules, triggering a cellular response.

What are enzymatic proteins?

Plasma membrane proteins that catalyze metabolic reactions directly.

What is an isotonic solution?

One that does not cause a cell to change shape, as the concentration of solutes is equal inside and outside the cell.

What is a hypotonic solution?

A solution that causes a cell to swell as water enters the cell due to a lower concentration of solutes outside the cell.

What is a hypertonic solution?

A solution that causes a cell to shrink as water leaves the cell due to a higher concentration of solutes outside the cell.

What is the chemical equation for photosynthesis?

6CO₂ + 6H₂O + light energy → C₆H₁₂O₆ + 6O₂.

What are the reactants of photosynthesis?

Carbon dioxide (6CO₂), water (6H₂O), and light energy.

What are the products of photosynthesis?

Glucose (C₆H₁₂O₆) and oxygen (6O₂).

What is the chemical equation for cellular respiration?

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + energy (ATP).

What are the reactants of cellular respiration?

Glucose (C₆H₁₂O₆) and oxygen (6O₂).

What are the products of cellular respiration?

Carbon dioxide (6CO₂), water (6H₂O), and energy (ATP).

How does ATP play a role in metabolism?

ATP provides the energy necessary for various metabolic processes.

What is the cell cycle?

The cell cycle consists of interphase (G₁, S, G₂) and mitotic phase (M).

What are the phases of mitosis?

Prophase, metaphase, anaphase, and telophase.

What is meiosis?

A type of cell division that reduces the chromosome number by half, resulting in the formation of haploid cells.

Why is meiosis important for fertilization?

It produces haploid gametes that combine during fertilization to form a diploid zygote.

How does sexual reproduction relate to biodiversity?

It increases biodiversity by combining genetic material from two parents.

How does genetic variation contribute to evolution?

It increases the chances of survival for some individuals in changing environments.

What is the nuclear envelope?

A double membrane that encloses the nucleus in eukaryotic cells.

What happens during prophase?

The nuclear envelope begins to break down, chromosomes condense, and the mitotic spindle begins to form.

What occurs during prometaphase?

The nuclear envelope fully dissolves, and spindle fibers attach to kinetochores on chromosomes.

What is metaphase?

The stage where chromosomes align at the cell's equatorial plane.

What happens during anaphase?

Sister chromatids are pulled apart toward opposite poles.

What occurs during telophase?

Chromatids reach the poles, de-condense into chromatin, and the nuclear envelope reforms.

What is cytokinesis in animal cells?

The process where a cleavage furrow forms, pinching the cell membrane.

How does cytokinesis differ in plant cells?

A cell plate forms in the middle of the cell, which develops into a new cell wall.

What is the G1 phase?

The first stage of the cell cycle where the cell grows and synthesizes organelles.

What occurs during the S phase?

DNA replication takes place, resulting in duplicated chromosomes.

What is the G2 phase?

The second gap phase where the cell continues to grow and checks for errors.

What is the M phase?

The phase of the cell cycle that includes mitosis and cytokinesis.

Define cell division.

The process by which a parent cell divides into two daughter cells.

What is the G1 checkpoint?

A control mechanism that checks for sufficient nutrients, growth signals, and intact DNA.

What does the G2 checkpoint do?

It checks for errors in the duplicated chromosomes before mitosis.

What is the M checkpoint?

A checkpoint that verifies that chromosomes are correctly aligned on the metaphase plate and that spindle fibers are properly attached before anaphase begins.

What are proto-oncogenes?

Genes that promote cell division and can become oncogenes when mutated; cyclins are an example that regulate the cell cycle.

What are tumor suppressor genes?

Genes that prevent uncontrolled cell division; examples include p53 and p27, which act as 'off switches' for the cell cycle.

What is the role of p53?

Known as the 'guardian of the genome,' it halts the cell cycle if DNA is damaged and can initiate apoptosis if the damage is irreparable.

What is the function of p27?

It regulates the cell cycle by inhibiting cyclin-dependent kinases, preventing premature entry into the S phase.

How can mutations in cyclins cause cancer?

Mutations can lead to uncontrolled cell division, contributing to cancer development.

How do tumor suppressor gene mutations lead to cancer?

Mutations may prevent the cell from halting the cycle in response to DNA damage, leading to uncontrolled growth.