science extras Flashcards
What is the most specific level of biological classification?
Species
Species refers to a group of organisms that can interbreed and produce fertile offspring.
What is the most general level of biological classification?
Kingdom
The kingdom encompasses multiple phyla.
What is the correct order of biological classification from broad to specific?
Kingdom, Phylum, Class, Order, Family, Genus, Species
This order can be remembered with the mnemonic ‘King Phillip Cried Out For Goodness Sakes’.
What falls directly below the kingdom in biological classification?
Phylum
The correct order is Kingdom → Phylum → Class → Order → Family → Genus → Species.
What level groups similar species?
Family
Families group similar species based on shared traits.
What is directly above the organ level in biological structures?
Organ systems
Organ systems consist of multiple organs working together.
What is made up of cells?
Tissues
Tissues are composed of similar cells that work together to perform a function.
What modifies polysaccharides and glycoproteins?
Golgi apparatus
The Golgi apparatus modifies, sorts, and packages macromolecules.
What is the function of the vacuole in plant cells?
Stores water, nutrients, and waste
The vacuole also maintains turgor pressure in plant cells.
Which phase of meiosis is characterized by the separation of homologous chromosomes?
Anaphase I
In Anaphase I, homologous chromosomes (pairs of maternal and paternal chromosomes) are separated and pulled to opposite poles. This is different from Anaphase II, where sister chromatids separate.
In which stage of mitosis do the centromeres split and sister chromatids separate?
Anaphase
During Anaphase, the centromeres split, allowing the sister chromatids to be pulled to opposite poles by spindle fibers, ensuring that each daughter cell receives an identical set of chromosomes.
Which of the following processes reduces the chromosome number by half?
Meiosis
Meiosis reduces the chromosome number from diploid (2n) to haploid (n), ensuring that gametes (sperm and egg cells) contain only half the genetic material, which is restored upon fertilization.
In which stage of mitosis does the cleavage furrow or cell plate begin to form?
Telophase
During Telophase, the nuclear envelope re-forms, and the cleavage furrow (in animal cells) or cell plate (in plant cells) begins to develop, preparing the cell for cytokinesis.
During which phase of meiosis do tetrads form and crossing over occurs?
Prophase I
Tetrads (pairs of homologous chromosomes) form during Prophase I, allowing for crossing over, which increases genetic diversity by exchanging segments between homologous chromosomes.
Which event is unique to meiosis and is not seen in mitosis?
Synapsis of homologous chromosomes
Synapsis is the pairing of homologous chromosomes during Prophase I of meiosis, allowing for crossing over, which does not occur in mitosis.
In which phase of mitosis does the nuclear envelope disintegrate and chromosomes become visible?
Prophase
During Prophase, chromatin condenses into visible chromosomes, and the nuclear envelope breaks down, allowing spindle fibers to attach to the chromosomes.
Which phase of meiosis involves the alignment of tetrads at the center of the cell?
Metaphase I
During Metaphase I, homologous chromosome pairs (tetrads) line up at the metaphase plate, ensuring proper segregation during Anaphase I.
During which phase of mitosis do sister chromatids become maximally condensed and clearly visible under the microscope?
Prophase
Prophase is when chromosomes condense and become distinct under a microscope, making them easy to observe for structural analysis.
At the end of Meiosis I, the resulting cells are:
Haploid and genetically different
Meiosis I results in two haploid cells, each containing half the original chromosome number. These cells are genetically unique due to crossing over and independent assortment.
In mitosis, what ensures that each daughter cell gets a complete set of chromosomes?
DNA replication during interphase
DNA is replicated during the S phase of interphase to ensure that, after mitosis, each daughter cell receives a full set of identical chromosomes.
Which phase of meiosis introduces genetic variability through the random alignment of maternal and paternal chromosomes?
Metaphase I
During Metaphase I, homologous chromosomes align randomly along the metaphase plate. This independent assortment contributes to genetic variation.
In meiosis, when do homologous chromosomes pair up?
Prophase I
During Prophase I, homologous chromosomes pair up and form tetrads, allowing crossing over to occur, which contributes to genetic diversity.
What is the primary function of mRNA?
Translation
mRNA carries genetic information from DNA and serves as a template for protein synthesis during translation.
How many genes do humans approximately have?
20,000
Humans have about 20,000-25,000 genes, coding for various proteins and regulating biological processes.
If a trait is NOT expressed in the presence of a dominant allele, it is referred to as:
Recessive
Recessive traits only appear when an individual has two copies of the recessive allele (homozygous recessive, aa).
If a gene is present on one of the first 22 pairs of human chromosomes, it is said to be:
Autosomal
Autosomal genes are located on chromosomes 1-22, while genes on the 23rd pair (X or Y chromosome) are sex-linked.
Mendel’s Law that states alleles for different traits are distributed to sex cells independently is:
Independent Assortment
Mendel’s Law of Independent Assortment states that genes for different traits separate independently during gamete formation, creating genetic diversity.
What term describes the situation where multiple genes determine a single trait?
Polygenic Inheritance
Polygenic inheritance involves multiple genes influencing a trait, such as height, skin color, or eye color.
If both parents are heterozygous for a trait, what is the probability that an offspring will be homozygous dominant?
25%
In a Punnett square (Aa × Aa), the offspring ratio is: * AA (homozygous dominant) - 25% * Aa (heterozygous) - 50% * aa (homozygous recessive) - 25%.
In a dihybrid cross involving two heterozygous genes (AaBb × AaBb), what is the probability of producing an offspring that is homozygous dominant for both traits?
1/16
A dihybrid cross (AaBb × AaBb) produces offspring in a 9:3:3:1 ratio, where only 1 out of 16 (AABB) is homozygous dominant for both traits.
Which of the following best describes a trait that is determined by more than two genes?
Polygenic Inheritance
Traits like height and eye color result from multiple genes interacting, making them polygenic traits rather than controlled by a single gene.
What inheritance pattern does the ABO blood group system demonstrate due to the presence of three different alleles?
Multiple Alleles
The ABO blood system (IA, IB, i) follows multiple allele inheritance because there are more than two possible alleles for one gene.
When an individual’s phenotype is influenced by more than one pair of genes, this is known as:
Polygenic Inheritance
Multiple gene pairs contribute to polygenic traits, resulting in continuous variation in characteristics like skin tone or intelligence.
An organism’s observable characteristics are determined by its:
Both genotype and environment
Phenotype (observable traits) is determined by both genetic makeup (genotype) and environmental influences (e.g., nutrition affecting height).
If an individual exhibits a blend of two parental traits, this is most likely a result of:
Incomplete Dominance
In incomplete dominance, the heterozygous phenotype is a blend of both alleles (e.g., red and white flowers producing pink offspring).
What bond forms between two monosaccharide units in a disaccharide?
Glycosidic bond
A glycosidic bond forms between two monosaccharides during dehydration synthesis, linking them into a disaccharide (e.g., sucrose, maltose, lactose).
Which carbohydrate is primarily stored in the liver and muscles for energy?
Glycogen
Glycogen is the storage form of glucose in animals, found mainly in the liver and muscles, providing a quick energy source.
What level of protein structure involves the sequence of amino acids in the polypeptide chain?
Primary
Primary structure refers to the specific sequence of amino acids in a protein, determining its final shape and function.
Which of the following is NOT a disaccharide?
Ribose
Ribose is a monosaccharide, not a disaccharide. Disaccharides include sucrose, lactose, and maltose.
Which carbohydrate is primarily a structural molecule in the cell walls of plants?
Cellulose
Cellulose is a polysaccharide that forms the rigid cell walls of plants, providing structural support.
Which level of protein structure is determined by the spatial arrangement of multiple polypeptide chains?
Quaternary
Quaternary structure involves multiple polypeptide chains assembling to form a functional protein complex (e.g., hemoglobin).
Lactose is composed of which two monosaccharides?
Glucose and galactose
Lactose (milk sugar) is a disaccharide composed of glucose and galactose.
The specific sequence of which molecules determines the function of a protein?
Amino acids
The order of amino acids in a protein determines its folding and function.
Which level of protein structure involves the alpha-helix and beta-pleated sheet formations?
Secondary
The secondary structure of proteins consists of alpha-helices and beta-pleated sheets, formed by hydrogen bonding between amino acids.
Which carbohydrate form is linear and unbranched?
Cellulose
Cellulose is a linear, unbranched polysaccharide that provides structural support in plants.
Which level of protein structure is determined by interactions between side chains of amino acids?
Tertiary
Tertiary structure is formed by interactions between side chains (R groups) of amino acids, stabilizing the protein’s 3D shape.
The molecule that provides quick energy for cells and is a product of photosynthesis is:
Glucose
Glucose is the primary energy source for cells and is produced in photosynthesis.
Which carbohydrate form provides plants with their rigid structure?
Cellulose
Cellulose is a structural polysaccharide found in plant cell walls, making plants rigid and strong.
Which protein aids in the coagulation of blood?
Fibrinogen
Fibrinogen is a blood-clotting protein that helps form fibrin strands to stop bleeding.
Which disease is non-infectious and cannot be spread from person to person?
Asthma
Asthma is a chronic respiratory condition caused by environmental factors, genetics, or allergies. It is not caused by an infectious agent and cannot be spread.
Which of the following is a single-celled eukaryotic organism?
Protozoans
Protozoans are single-celled eukaryotic organisms that can move independently and may cause diseases like malaria and amoebic dysentery.
Diseases like HIV/AIDS and influenza are contagious. What does ‘contagious’ mean in this context?
Easily spread from person to person
Contagious diseases can spread easily between individuals through direct contact, airborne droplets, or bodily fluids.
Which type of microscope would be most appropriate for viewing a live amoeba in a water sample?
Light microscope
A light microscope is best for observing living specimens in liquid, such as an amoeba, as it does not require sample preparation that could kill the organism.
Which micro-organism forms a part of the natural human gut flora and can be beneficial?
Bacteria
Certain bacteria in the gut, such as Lactobacillus and Bifidobacterium, aid in digestion, vitamin production, and immune function.
What is the primary method of transmission for a disease like rabies?
Through infected saliva
Rabies is transmitted through the bite or saliva of an infected animal, introducing the virus into the bloodstream.
What type of infectious agent is responsible for conditions like candidiasis?
Fungi
Candidiasis is caused by Candida, a type of fungus that can overgrow and lead to infections in the mouth (thrush) and genitals (yeast infections).
Which micro-organism is responsible for causing bacterial pneumonia?
Bacteria
Bacterial pneumonia is most commonly caused by Streptococcus pneumoniae, which infects the lungs and causes respiratory distress.
How do infectious diseases like the common cold primarily spread?
Direct contact
The common cold is primarily spread through direct contact with infected individuals, contaminated surfaces, or respiratory droplets.
Which micro-organism causes diseases by producing toxins?
Bacteria
Some bacteria (e.g., Clostridium botulinum, Staphylococcus aureus) release toxins that cause illnesses like botulism and food poisoning.
Which type of infectious agent is responsible for diseases like AIDS?
Viruses
AIDS is caused by the Human Immunodeficiency Virus (HIV), which attacks the immune system and makes individuals vulnerable to infections.
Which disease is non-infectious and results from an individual’s own immune system attacking healthy cells?
Rheumatoid arthritis
Rheumatoid arthritis is an autoimmune disorder, meaning the immune system mistakenly attacks the body’s own tissues, causing inflammation and joint damage.
Which type of microscope provides a detailed, high-resolution view of small specimens but kills the sample in the process?
Transmission electron microscope
Transmission electron microscopes (TEMs) provide high-resolution images of internal cellular structures, but require sample preparation that kills the specimen.
Which step in the scientific method involves formulating a hypothesis based on previous knowledge or observations?
Deduction
Deduction involves forming a hypothesis or theory based on prior observations or existing knowledge to explain the phenomena.
In the scientific method, which step involves identifying the problem or question?
Introduction
The introduction step of the scientific method involves identifying and stating the problem or research question that will be investigated.
What kind of relationship exists when an increase in one variable leads to a decrease in another?
Negative correlation
A negative correlation means that as one variable increases, the other decreases, demonstrating an inverse relationship.
Which term describes a factor that is not the focus of an experiment but might affect its results?
Confounding variable
A confounding variable is an external factor that can affect the dependent variable but isn’t being tested directly in the experiment.
What is the primary purpose of the deduction step in the scientific method?
Drawing conclusions from the data
The deduction step involves drawing conclusions or forming generalized statements based on the data collected in the testing phase.
In an experiment, the introduction primarily serves to:
Explain the background and purpose
The introduction provides the background information, defines the research problem, and sets the purpose of the experiment.
When two variables increase in tandem, they share what kind of relationship?
Positive correlation
A positive correlation occurs when both variables increase together, showing a direct relationship.
The primary reason to use a control group in an experiment is to:
Have a group to compare with the treatment group
The control group serves as a baseline for comparison, allowing researchers to determine the effects of the experimental treatment.
In a correlation between increased study hours and higher exam scores, which statement is accurate?
A relationship exists between study hours and exam scores, but it doesn’t confirm causation.
Correlation shows a relationship but does not establish causation, meaning the relationship may not imply that study hours directly cause better exam scores.
In the observation step of the scientific method, a researcher is primarily:
Identifying patterns or phenomena
Observation involves identifying and recording patterns or phenomena that will lead to the formulation of a hypothesis.
What can you infer about the poles of two magnets that repel each other?
Both are north poles or both are south poles.
Like poles repel each other, meaning that if two magnets repel, they must both have the same pole facing each other (either both north or both south). Opposite poles (north and south) attract.
What might you predict about the population of prey if the number of predators decreases in a closed system?
It will increase.
Predators help control prey populations. If predator numbers decrease, fewer prey are being consumed, leading to a population increase of the prey species.
What kind of energy is at its maximum when a pendulum momentarily stops at the peak of its swing?
Potential energy.
At the highest point of its swing, the pendulum has stopped moving and has no kinetic energy. All of its energy is stored as potential energy due to gravity.
What might you predict about a person’s bone health if their diet is deficient in Vitamin D?
Reduced bone density and increased risk of fractures.
Vitamin D is essential for calcium absorption, which is crucial for maintaining strong bones. A deficiency leads to weaker bones and an increased risk of fractures.
What will you observe about the roots of a plant that exhibits geotropism when placed horizontally?
Roots will grow downwards.
Geotropism (gravitropism) is a plant’s growth response to gravity. Roots exhibit positive geotropism, meaning they grow towards gravity (downward), while stems show negative geotropism, growing against gravity (upward).
