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?

Videos can summarize large topics quickly. Signup and view all the answers

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

It effectively teaches complex material in a short time. Signup and view all the answers

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

Different proteins cannot be made from the same DNA segment. Signup and view all the answers

What does splicing indicate about RNA processing in cells?

Only exons contribute to the final protein product. Signup and view all the answers

How does splicing vary between different cell types?

Cells may include or omit different exons depending on protein needs. Signup and view all the answers

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

It allows for faster transmission by enabling charges to jump across nodes. Signup and view all the answers

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

The initiation of an action potential. Signup and view all the answers

How do neurotransmitters affect the receiving neuron?

They can block or trigger another action potential. Signup and view all the answers

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

They allow for rapid signal conduction along the axon. Signup and view all the answers

What happens at the terminal button of a neuron?

It connects with the dendrites of the next neuron. Signup and view all the answers

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

Schwann cells Signup and view all the answers

What fundamental process enables neurons to communicate with each other?

Chemical signals called neurotransmitters. Signup and view all the answers

What is the primary function of the myelin sheath?

To insulate the axon for faster signal propagation. Signup and view all the answers

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

Transcription Signup and view all the answers

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

23 Signup and view all the answers

What are different versions of a gene called?

Alleles Signup and view all the answers

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

Dominant trait Signup and view all the answers

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

Intermediate inheritance Signup and view all the answers

What type of cells are produced through meiosis?

Haploid cells Signup and view all the answers

What is the function of histones in relation to DNA?

To coiled DNA Signup and view all the answers

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

Codominance Signup and view all the answers

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

Mitosis Signup and view all the answers

Which sex chromosomes do females possess?

XX Signup and view all the answers

What is the result of crossing over during meiosis?

Genetically different haploid cells Signup and view all the answers

What is the primary function of mRNA?

To carry genetic information from DNA 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?

Most children will have brown eyes, some may have blue Signup and view all the answers

What is the primary role of enzymes in biological processes?

They act as catalysts to speed up chemical reactions. Signup and view all the answers

Which characteristic differentiates living organisms from non-living objects?

Ability to metabolize food. Signup and view all the answers

What are the two main categories of cellular organisms?

Eukaryotes and Prokaryotes. Signup and view all the answers

What is homeostasis?

The process of maintaining stable internal conditions. Signup and view all the answers

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

Their structure can be altered by environmental changes. Signup and view all the answers

What are the building blocks of proteins?

Amino acids. Signup and view all the answers

What kind of molecules are carbohydrates primarily used for?

Providing quick energy. Signup and view all the answers

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

A unique name consisting of a genus and a species. Signup and view all the answers

Which organisms are classified as prokaryotes?

Bacteria. Signup and view all the answers

What do lipids primarily function as in biological organisms?

Membrane components and energy storage. Signup and view all the answers

How do living organisms respond to changes in their environment?

They adapt and evolve over time. Signup and view all the answers

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

They provided chemicals for the origin of life. Signup and view all the answers

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

Eukaryotes. Signup and view all the answers

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

Proteins. Signup and view all the answers

What is the primary function of the cell membrane?

To allow selective passage of substances in and out of the cell Signup and view all the answers

How does water move in relation to solute concentration?

It can move to areas of high solute concentration Signup and view all the answers

What provides the energy for moving particles against their gradient?

Adenosine Triphosphate (ATP) Signup and view all the answers

Which statement accurately describes humans in terms of nutrition?

They rely on other organisms for glucose. Signup and view all the answers

What role do chloroplasts play in plant cells?

They absorb light and help produce glucose. Signup and view all the answers

What is the structure of ATP?

A nucleotide with a phosphate group, sugar, and nitrogenous base Signup and view all the answers

How are genes related to proteins?

Genes code for proteins by specifying sequences of amino acids. Signup and view all the answers

What is the role of mRNA in protein synthesis?

To carry the gene's information from the nucleus to ribosomes Signup and view all the answers

Which molecule carries amino acids to the ribosome?

tRNA Signup and view all the answers

What happens during transcription?

RNA polymerase synthesizes an RNA strand from a DNA template Signup and view all the answers

What are codons?

Three base sequences in RNA that code for amino acids Signup and view all the answers

How is the genetic code held together within DNA?

By hydrogen bonds between nitrogenous bases Signup and view all the answers

What determines an organism’s traits?

The type of protein produced in its cells Signup and view all the answers

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

Autotrophs Signup and view all the answers

What is the primary purpose of meiosis in reproduction?

To create haploid gametes Signup and view all the answers

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

Interphase Signup and view all the answers

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

To check if the cell is healthy Signup and view all the answers

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

Change in the protein coded by the gene Signup and view all the answers

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

Duplication of the 21st chromosome Signup and view all the answers

How can mutations contribute to the process of evolution?

They can enhance an organism's fitness Signup and view all the answers

What defines a bacterial cell?

It is a prokaryote Signup and view all the answers

What distinguishes viruses from living organisms?

They do not consist of cells Signup and view all the answers

How do antibiotics affect bacterial infections?

They kill bacteria Signup and view all the answers

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

To conduct electrical signals Signup and view all the answers

What defines action potentials in neurons?

They are all or nothing events Signup and view all the answers

What happens during depolarization in a neuron?

The electric potential becomes less negative Signup and view all the answers

What is the charge of a neuron at resting potential?

-70 mV Signup and view all the answers

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

The antibiotic may no longer be effective Signup and view all the answers

Which of the following best describes 'apoptosis'?

Cell destruction due to malfunctions Signup and view all the answers

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.