Biology Summary Overview
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Questions and Answers

What is one way DNA can create multiple proteins?

  • By changing its sequence.
  • By replicating itself.
  • Through the use of different enzymes.
  • By splicing RNA in different ways. (correct)

What are exons and introns in the context of RNA?

  • Exons are coding parts, while introns are non-coding portions. (correct)
  • Both are coding areas that create proteins.
  • Introns contribute to the final protein sequence.
  • Introns are found only in prokaryotic cells, while exons are in eukaryotic cells.

What happens during RNA splicing?

  • All exons are merged into one continuous strand.
  • Both exons and introns are discarded.
  • No changes are made to the RNA structure.
  • Introns are removed, and some exons may also be discarded. (correct)

Why might a student prefer watching a video over reading a biology book?

<p>Videos can summarize large topics quickly. (B)</p> Signup and view all the answers

What is suggested by the comment regarding the effectiveness of the video?

<p>It effectively teaches complex material in a short time. (D)</p> Signup and view all the answers

What is a misconception about DNA's role in protein synthesis?

<p>Different proteins cannot be made from the same DNA segment. (B)</p> Signup and view all the answers

What does splicing indicate about RNA processing in cells?

<p>Only exons contribute to the final protein product. (D)</p> Signup and view all the answers

How does splicing vary between different cell types?

<p>Cells may include or omit different exons depending on protein needs. (A)</p> Signup and view all the answers

What effect does the presence of myelin sheath have on signal transmission in neurons?

<p>It allows for faster transmission by enabling charges to jump across nodes. (C)</p> Signup and view all the answers

What is 'depolarization' in the context of neuron signaling?

<p>The initiation of an action potential. (B)</p> Signup and view all the answers

How do neurotransmitters affect the receiving neuron?

<p>They can block or trigger another action potential. (B)</p> Signup and view all the answers

What role do the nodes of Ranvier play in neuron function?

<p>They allow for rapid signal conduction along the axon. (D)</p> Signup and view all the answers

What happens at the terminal button of a neuron?

<p>It connects with the dendrites of the next neuron. (A)</p> Signup and view all the answers

Which component is crucial for insulating the axon in certain neurons?

<p>Schwann cells (C)</p> Signup and view all the answers

What fundamental process enables neurons to communicate with each other?

<p>Chemical signals called neurotransmitters. (B)</p> Signup and view all the answers

What is the primary function of the myelin sheath?

<p>To insulate the axon for faster signal propagation. (D)</p> Signup and view all the answers

What is the process of copying a gene onto mRNA called?

<p>Transcription (D)</p> Signup and view all the answers

How many different chromosomes does the entire human genome consist of?

<p>23 (D)</p> Signup and view all the answers

What are different versions of a gene called?

<p>Alleles (D)</p> Signup and view all the answers

Which trait is represented by an uppercase letter in genetic notation?

<p>Dominant trait (B)</p> Signup and view all the answers

What genetic phenomenon occurs when a red and a white snapdragon are crossed?

<p>Intermediate inheritance (C)</p> Signup and view all the answers

What type of cells are produced through meiosis?

<p>Haploid cells (A)</p> Signup and view all the answers

What is the function of histones in relation to DNA?

<p>To coiled DNA (A)</p> Signup and view all the answers

Which type of inheritance occurs when both phenotypes are equally expressed?

<p>Codominance (D)</p> Signup and view all the answers

What type of cell division results in two identical diploid cells?

<p>Mitosis (D)</p> Signup and view all the answers

Which sex chromosomes do females possess?

<p>XX (D)</p> Signup and view all the answers

What is the result of crossing over during meiosis?

<p>Genetically different haploid cells (C)</p> Signup and view all the answers

What is the primary function of mRNA?

<p>To carry genetic information from DNA (B)</p> Signup and view all the answers

If both parents carry one dominant brown allele and one recessive blue allele, what eye color is likely for their children?

<p>Most children will have brown eyes, some may have blue (D)</p> Signup and view all the answers

What is the primary role of enzymes in biological processes?

<p>They act as catalysts to speed up chemical reactions. (C)</p> Signup and view all the answers

Which characteristic differentiates living organisms from non-living objects?

<p>Ability to metabolize food. (A), Being composed of cells. (B), Ability to reproduce. (D)</p> Signup and view all the answers

What are the two main categories of cellular organisms?

<p>Eukaryotes and Prokaryotes. (D)</p> Signup and view all the answers

What is homeostasis?

<p>The process of maintaining stable internal conditions. (C)</p> Signup and view all the answers

Why do enzymes require specific environmental conditions, such as pH?

<p>Their structure can be altered by environmental changes. (D)</p> Signup and view all the answers

What are the building blocks of proteins?

<p>Amino acids. (A)</p> Signup and view all the answers

What kind of molecules are carbohydrates primarily used for?

<p>Providing quick energy. (A)</p> Signup and view all the answers

What is the definition of a scientific name in biological classification?

<p>A unique name consisting of a genus and a species. (A)</p> Signup and view all the answers

Which organisms are classified as prokaryotes?

<p>Bacteria. (B)</p> Signup and view all the answers

What do lipids primarily function as in biological organisms?

<p>Membrane components and energy storage. (B)</p> Signup and view all the answers

How do living organisms respond to changes in their environment?

<p>They adapt and evolve over time. (A), They maintain homeostasis. (D)</p> Signup and view all the answers

What is the significance of hydrothermal vents in early Earth's history?

<p>They provided chemicals for the origin of life. (C)</p> Signup and view all the answers

In which living organisms is DNA contained within a defined nucleus?

<p>Eukaryotes. (B)</p> Signup and view all the answers

Which biomolecule is primarily responsible for the structure and function of cells?

<p>Proteins. (C)</p> Signup and view all the answers

What is the primary function of the cell membrane?

<p>To allow selective passage of substances in and out of the cell (B)</p> Signup and view all the answers

How does water move in relation to solute concentration?

<p>It can move to areas of high solute concentration (A)</p> Signup and view all the answers

What provides the energy for moving particles against their gradient?

<p>Adenosine Triphosphate (ATP) (C)</p> Signup and view all the answers

Which statement accurately describes humans in terms of nutrition?

<p>They rely on other organisms for glucose. (B)</p> Signup and view all the answers

What role do chloroplasts play in plant cells?

<p>They absorb light and help produce glucose. (D)</p> Signup and view all the answers

What is the structure of ATP?

<p>A nucleotide with a phosphate group, sugar, and nitrogenous base (C)</p> Signup and view all the answers

How are genes related to proteins?

<p>Genes code for proteins by specifying sequences of amino acids. (B)</p> Signup and view all the answers

What is the role of mRNA in protein synthesis?

<p>To carry the gene's information from the nucleus to ribosomes (C)</p> Signup and view all the answers

Which molecule carries amino acids to the ribosome?

<p>tRNA (B)</p> Signup and view all the answers

What happens during transcription?

<p>RNA polymerase synthesizes an RNA strand from a DNA template (B)</p> Signup and view all the answers

What are codons?

<p>Three base sequences in RNA that code for amino acids (C)</p> Signup and view all the answers

How is the genetic code held together within DNA?

<p>By hydrogen bonds between nitrogenous bases (D)</p> Signup and view all the answers

What determines an organism’s traits?

<p>The type of protein produced in its cells (B)</p> Signup and view all the answers

What type of organism is capable of producing its own glucose?

<p>Autotrophs (D)</p> Signup and view all the answers

What is the primary purpose of meiosis in reproduction?

<p>To create haploid gametes (C)</p> Signup and view all the answers

During which phase of the cell cycle does a cell spend most of its time?

<p>Interphase (A)</p> Signup and view all the answers

What is the role of proteins like p53 and cyclin in the cell cycle?

<p>To check if the cell is healthy (A)</p> Signup and view all the answers

What is a common result of a gene mutation during DNA replication?

<p>Change in the protein coded by the gene (D)</p> Signup and view all the answers

What is the most well-known chromosomal mutation associated with Down syndrome?

<p>Duplication of the 21st chromosome (D)</p> Signup and view all the answers

How can mutations contribute to the process of evolution?

<p>They can enhance an organism's fitness (B)</p> Signup and view all the answers

What defines a bacterial cell?

<p>It is a prokaryote (D)</p> Signup and view all the answers

What distinguishes viruses from living organisms?

<p>They do not consist of cells (D)</p> Signup and view all the answers

How do antibiotics affect bacterial infections?

<p>They kill bacteria (C)</p> Signup and view all the answers

What is the primary function of neurons in the nervous system?

<p>To conduct electrical signals (D)</p> Signup and view all the answers

What defines action potentials in neurons?

<p>They are all or nothing events (A)</p> Signup and view all the answers

What happens during depolarization in a neuron?

<p>The electric potential becomes less negative (B)</p> Signup and view all the answers

What is the charge of a neuron at resting potential?

<p>-70 mV (A)</p> Signup and view all the answers

What can happen if bacteria mutate and become resistant to antibiotics?

<p>The antibiotic may no longer be effective (D)</p> Signup and view all the answers

Which of the following best describes 'apoptosis'?

<p>Cell destruction due to malfunctions (D)</p> Signup and view all the answers

Flashcards

Transcription

The process of creating a copy of a gene's DNA sequence in the form of RNA. This is the first step in protein synthesis.

Translation

The process of interpreting the RNA sequence and building a protein based on its instructions. This is the second step in protein synthesis.

Exons

The coding parts of RNA that are used to build proteins.

Introns

The non-coding parts of RNA that are removed before protein synthesis.

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RNA splicing

The process of removing introns from pre-mRNA to create mature mRNA. This ensures only coding sequences are used during translation.

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Alternative splicing

A segment of DNA that can be used to create multiple proteins depending on the cell it's being expressed in.

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Protein folding

The process of creating a functional protein from an amino acid chain. This involves folding and modification of the protein.

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Gene expression

The process by which cells use genetic information to create new cells.

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Cell Membrane

A membrane that surrounds a cell and regulates what enters and exits the cell. It's composed of two layers of phospholipid molecules, with polar heads facing outwards and nonpolar tails facing inwards.

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Diffusion

The movement of molecules from an area of high concentration to an area of low concentration.

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Ion Channels

Channels in the cell membrane that allow specific ions to pass through.

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Active Transport

The process of moving molecules across a membrane against their concentration gradient, from low concentration to high concentration. It requires energy.

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ATP

A high-energy molecule that cells use as their main source of energy.

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Cellular Respiration

A process by which cells break down glucose (sugar) in the presence of oxygen to produce ATP, carbon dioxide, and water.

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Heterotrophs

Organisms that obtain energy by consuming other organisms.

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Autotrophs

Organisms that can produce their own food through photosynthesis.

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Photosynthesis

A process by which plants use sunlight, water, and carbon dioxide to produce glucose and oxygen.

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Chlorophyll

A green pigment found in chloroplasts of plant cells that absorbs sunlight for photosynthesis.

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DNA

A molecule that carries genetic information in the form of a sequence of nucleotides.

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Nucleotide

The building blocks of DNA and RNA, each consisting of a phosphate group, a sugar, and a nitrogenous base.

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Gene

A section of DNA that codes for a specific protein.

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RNA

A molecule similar to DNA that carries genetic information from the nucleus to ribosomes.

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Chemical reactions

The process of breaking down or combining substances, often with the help of enzymes.

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Enzymes

Special proteins that speed up chemical reactions by lowering activation energy.

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Homeostasis

The ability of an organism to maintain stable internal conditions, like temperature and pH, despite external changes.

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Eukaryotic cell

The type of cell that has a nucleus and other membrane-bound organelles.

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Prokaryotic cell

The type of cell that lacks a nucleus and other membrane-bound organelles, with DNA floating freely in the cytoplasm.

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Taxonomic ranks

A system for classifying living things based on their shared characteristics.

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Scientific name

The unique scientific name given to every species, consisting of the genus and species name.

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Cell

The basic unit of life, capable of carrying out all life functions independently.

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Nucleus

A specialized organelle found in eukaryotic cells, containing the cell's genetic material (DNA).

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Cytoplasm

The fluid inside a cell, where organelles are suspended.

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Carbohydrates

Molecules that provide quick energy for cells, like sugars and starches.

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Lipids

Molecules that store long-term energy and form cell membranes, like fats and oils.

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Proteins

Molecules that build tissues, muscles, and enzymes, made up of amino acids.

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Nucleic acids

Molecules that store and transmit genetic information, like DNA and RNA.

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Action Potential

The process where a signal travels down a neuron, caused by the movement of ions across the cell membrane.

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Myelin Sheath

Fatty substance that covers some axons, speeding up the transmission of signals by allowing them to 'jump' between gaps called nodes of Ranvier.

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Nodes of Ranvier

Tiny gaps in the myelin sheath, where the signal jumps across.

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Terminal Buttons

Specialized structures at the end of an axon that transmit signals to other neurons.

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Neurotransmitters

Chemicals released from terminal buttons that communicate with the next neuron.

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Synaptic Cleft

The space between the terminal button of one neuron and the dendrite of the next.

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Postsynaptic Potential

A process that occurs in the dendrite of the next neuron after receiving neurotransmitters, which can lead to another action potential.

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Repolarization

The process by which a neuron returns to its resting state after an action potential.

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Gene regulation

The process of turning genes on or off, regulating the production of specific proteins in different cells.

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Histones

Proteins that DNA wraps around to form chromatin.

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Chromatin

A thread-like structure consisting of DNA tightly coiled around histones.

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Chromosomes

Compact, tightly packed units of DNA that are visible during cell division.

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Homologous chromosomes

Chromosomes that carry the same genes in the same location, one from the mother and one from the father.

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Alleles

Alternate forms of a gene that occupy the same locus on homologous chromosomes.

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Dominant allele

An allele that masks the expression of a recessive allele when both are present.

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Recessive allele

An allele that is only expressed when two copies are present.

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Intermediate inheritance

The inheritance pattern where a heterozygote expresses a phenotype intermediate between the two homozygous phenotypes.

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Codominance

The inheritance pattern where both alleles are expressed equally in the heterozygote.

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Sex chromosomes

A pair of chromosomes that determine sex. Females have two X chromosomes (XX) and males have an X and a Y chromosome (XY).

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Mitosis

The process by which a cell divides to produce two identical daughter cells. It involves the duplication of chromosomes and the division of the cytoplasm.

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Meiosis

The process by which a cell divides to produce four daughter cells, each with half the number of chromosomes as the parent cell. It involves two rounds of division and is essential for sexual reproduction.

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Interphase

The stage of the cell cycle where the cell grows, doubles its organelles and replicates its DNA in preparation for cell division.

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Cell Cycle Control

A complex protein network that regulates the cell cycle and ensures that cells divide only when appropriate. It involves checkpoints that monitor the cell's status and prevent errors in DNA replication and cell division.

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Apoptosis

Programmed cell death, a natural and controlled process that eliminates damaged or unwanted cells. It involves a series of biochemical events that lead to cell disassembly and destruction.

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Cancer

Uncontrolled cell growth and division, leading to the formation of tumors. It results from mutations that disrupt the cell cycle control mechanisms and allow cells to reproduce indefinitely.

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Gene Mutation

A permanent change in the DNA sequence of a gene, which can alter the protein coded for by that gene. They can occur spontaneously during DNA replication or be induced by environmental factors.

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Chromosomal Mutations

Changes in the structure or number of chromosomes, which can involve deletions, duplications, inversions, or translocations of DNA segments. They can lead to various genetic disorders.

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Natural Selection

The process by which organisms better adapted to their environment tend to survive and reproduce more successfully than those less adapted. It is the driving force behind evolution.

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Adaptation

The process by which organisms evolve to become better adapted to their environment through the accumulation of advantageous genetic changes over generations. It is a key feature of evolution.

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Bacteria

Single-celled organisms that lack a nucleus and other membrane-bound organelles. They are found in various environments and play important roles in ecosystems.

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Viruses

Non-living particles that can only replicate inside a host cell. They consist of genetic material enclosed in a protein coat and can cause a wide range of diseases.

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Symbiosis

A close and often long-term relationship between two different species where both species benefit. It is a common and important ecological interaction.

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Organ System

A complex network of specialized tissues and organs that work together to carry out essential life functions.

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Nervous System

The body's communication system, consisting of the brain, spinal cord and nerves. It receives and processes information from the environment and controls bodily functions.

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Neurons

Specialized cells that transmit electrical signals throughout the nervous system. They are responsible for communication and coordination within the body.

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Study Notes

Biology Summary

  • Biology studies life, essentially chemical processes within living organisms.
  • Living things are composed of molecules: carbohydrates (quick energy), lipids (long-term energy & membranes), proteins (tissues), and nucleic acids (DNA).
  • Enzymes, special proteins, act as catalysts, accelerating chemical reactions.
  • Characteristics of living things include energy production, growth/development, reproduction, and response to the environment.
  • All living things are composed of cells (eukaryotes or prokaryotes).
  • Eukaryotes have membrane-bound organelles (like the nucleus containing DNA) while prokaryotes do not.
  • Prokaryotes include bacteria and archaea; eukaryotes include protists, fungi, plants, and animals.
  • Taxonomy classifies living things based on evolutionary relationships.
  • Species are given scientific names (genus and species) for clarity.
  • Homeostasis is maintaining stable internal conditions.
  • Cells maintain homeostasis by balancing chemical concentrations, crucial for enzyme function.
  • Cell membranes are semi-permeable, regulating what enters and leaves the cell.
  • Diffusion allows small molecules to move from high to low concentration.
  • Active transport moves molecules against the concentration gradient using ATP energy.
  • Cellular respiration (in mitochondria) converts glucose and oxygen into water, carbon dioxide, and ATP (energy).
  • Plants (autotrophs) use photosynthesis (in chloroplasts) to produce glucose from sunlight, water, and carbon dioxide.
  • DNA is a double-stranded molecule with base pairs (A-T, C-G) that store genetic information.
  • Genes are segments of DNA that code for traits. Mutations can occur in DNA base sequences or entire chromosomes.
  • RNA copies genetic information from DNA (transcription) to the ribosomes.
  • Translation uses mRNA codons to assemble amino acids into a polypeptide chain, becoming proteins.

Protein Synthesis and Genes

  • Genes are recipes for proteins. Different proteins determine traits.
  • Eye colour is an example influenced by the OCA2 gene and resulting P-protein.
  • Information from DNA in the nucleus is carried to the ribosomes via mRNA.
  • Ribosomes use mRNA codons and tRNA to build a chain of amino acids called a polypeptide. The polypeptide folds into a protein.

Cell Division and Genetics

  • Mitosis creates identical copies of cells for growth and repair.
  • Meiosis produces gametes (sperm and egg cells) with half the number of chromosomes allowing for variety during sexual reproduction
  • Meiosis includes "crossing over" which exchanges genetic information between chromosome pairs.

Genetics and Inheritance

  • Chromosomes are tightly-coiled DNA organized around histones.
  • Every body cell has 2 copies of each chromosome (one from each parent), called homologous chromosomes.
  • Alleles are different versions of a gene, present on homologous chromosomes.
  • Alleles can be dominant or recessive determining traits expressed.
  • Dominant alleles are expressed even if only one copy is present.
  • Recessive alleles are expressed only when two copies are present.
  • Incomplete dominance and codominance involve blended or multiple traits expressed.
  • Sex chromosomes (X and Y) determine sex (XX for females, XY for males); X-linked genes are present in higher frequency in males.

Mutations and Evolution

  • Gene mutations are changes in DNA sequences that can be neutral, harmful, or beneficial.
  • Chromosomal mutations involve changes in chromosome structure
  • Natural selection drives evolution, favoring individuals with traits that improve their survival and reproduction.

Other Biological Concepts

  • Bacteria are single-celled organisms, treated with antibiotics.
  • Viruses are acellular and need a host to reproduce. They are not treated with antibiotics.
  • Organ systems in the human body work together for life sustaining functions.
  • Nervous systems use electrical signals (action potentials) transmitted along neurons.
  • Neurotransmitters transmit signals between neurons at synapses.

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Description

This quiz provides a comprehensive overview of biology, covering essential concepts about life and cellular processes. It includes information on living organisms, their chemical composition, characteristics, and classification. Explore the differences between eukaryotes and prokaryotes as well as the importance of homeostasis.

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