Life Sciences Flashcards
What is the biological hierarchy of the body?
Chemicals, cells, tissues, organs, organ systems, and organisms.
Chemicals help build ____.
Cells
What are cells?
The basic unit of life.
What are tissues?
Made up of cells that have a similar structure and function.
What are organs?
Made up of tissues that work together to carry out of specific function.
What are organ systems?
Group of organs that work together to carry out specific functions.
What are organisms?
Made up of one or more organ systems.
How many systems does the human body have?
11
What are the differences between prokaryotes and eukaryotes?
Prokaryotes don’t have a nucleus or membrane bound organelles, whereas eukaryotes have both.
What is the cell membrane (plasma membrane) of a cell?
A thin layer of protein and fat that surrounds the cell.
The cell membrane has ____ permeability. What does this mean?
Selective. It allows some substances to enter and exit the cell while it keeps other substances out.
What is the cytoplasm of a cell?
A gelatinous liquid that fills the inside of a cell. It’s a network if fibers that provides structural support for the cells and organelles. It also helps with cellular movement.
What is the Golgi apparatus of a cell?
An organelle that helps with packaging and transporting of molecules within the cell. It also helps process proteins and lipid molecules.
What are lysosomes of a cell?
Organelles that contain enzymes that break down food and other molecules. They aid in digestion and recycle old cell materials. They also destroy any invading bacteria as well as viruses.
What are the mitochondria of a cell?
Organelles that produce energy for the cell. They convert nutrients into ATP, which is the cell’s energy source.
What does ATP stand for?
Adenosine triphosphate
What is the nucleus of a cell?
An organelle that contains the cell’s hereditary information known as DNA. DNA is responsible for the cell’s growth, reproduction, and function.
What is the nucleolus of a cell?
An area inside the nucleus of a cell that is made up of RNA and proteins and is where ribosomes are made.
What are the ribosomes of a cell?
Intercellular structures made of both RNA and protein. Their primary function is protein synthesis.
Where are ribosomes located?
On the rough endoplasmic reticulum or floating around within the cytoplasm.
What cell component is primarily responsible for assembling proteins using instructions encoded in mRNA?
Ribosomes
What is the endoplasmic reticulum of a cell?
A large, dynamic structure that serves many roles in the cell including calcium storage, protein synthesis, and lipid metabolism.
What does the rough endoplasmic reticulum of a cell do?
It provides surface area for chemical reactions, and functions in protein synthesis and transport.
What makes the rough endoplasmic reticulum rough?
It is rough due to the surface covered in ribosomes.
What does the smooth endoplasmic reticulum of a cell do?
It makes cellular products like hormones and lipids and functions in detoxification. It doesn’t contain any ribosomes.
What is the vacuole of a cell?
The organelle that stores food, water, and other materials. It also helps maintain the shape of the cell.
What is mitosis?
The process of cell division that results in 2 genetically identical daughter cells.
What kinds of cells does mitosis produce?
Somatic cells also known as body cells.
What kinds of cells does meiosis produce?
Reproductive cells also known as gametes.
Both mitosis and meiosis start off as a ____ cell, designated by ____.
Diploid, 2n.
What is the cell cycle?
The sequence of events that the cell goes through in order to grow and divide.
What are the 5 phases of mitosis?
Interphase, prophase, metaphase, anaphase, and telophase.
What is the interphase phase of mitosis?
The first stage of the cell cycle. It is when the cell grows and carries out its normal functions. DNA starts to replicate.
What is the prophase phase of mitosis?
This is the second stage of the cell cycle. The chromosomes condense and become visible. The nuclear envelope also breaks down.
What is the metaphase phase of mitosis?
This is the third phase of the cell cycle. The chromosomes line up in the middle of the cell.
What is the anaphase phase of mitosis?
This is the fourth phase of the cell cycle. The chromosomes are pulled apart to opposite sides of the cell. Cell division begins.
What is the telophase phase of mitosis?
This is the fifth and final stage of the cell cycle. A new nuclear envelope forms around the chromosomes. The chromosomes uncoil and become less visible. The cell then divides into 2 daughter cells.
After the telophase phase of mitosis, what can the 2 daughter cells then do?
Enter into interphase all over again, in which the cell cycle continues repeatedly.
What is meiosis?
The process of division that results in 4 genetically identical daughter cells.
Unlike in mitosis, meiosis has ____ stages. What are they?
2, meiosis I and meiosis II.
What are the 5 stages of meiosis I?
Interphase I, prophase I, metaphase I, anaphase I, and telophase I.
What are the 4 stages of meiosis II?
Prophase II, metaphase II, anaphase II, and telophase II.
What is the prophase II stage of meiosis?
This is the sixth stage of meiosis. In this stage, the daughter cells contain half of the chromosomes from the original cells.
What is the metaphase II stage of meiosis?
This is the seventh stage of meiosis. In this stage, the chromosomes line up in the middle of the cell again.
What is the anaphase II stage of meiosis?
This is the eighth stage of meiosis. In this stage, the sister chromatids are pulled apart to opposite sides of the cell.
What is the telophase II stage of meiosis?
This is the ninth and final stage of meiosis. In this stage, the cells divide into 4 genetically diverse daughter cells also known as haploids.
Mitosis and meiosis are continuous processes that happen in ____ cells.
All
During which phase of meiosis does crossing over occur, contributing to genetic diversity by exchanging genetic material between homologous chromosomes?
Prophase I
What is the difference between mitosis and meiosis in terms of genetic outcome?
Mitosis results in 2 genetically identical diploid daughter cells, while meiosis produces 4 genetically unique haploid cells.
In meiosis, homologous chromosomes segregate during Anaphase I. What is the significance of this event in terms of genetic variation?
It allows for the random assortment of chromosomes, contributing to genetic diversity among offspring.
What are chromosomes?
They are long, thread-like structures that are round in the nucleus of the cell.
What do chromosomes consist of?
DNA and histone proteins.
How many chromosomes are in every cell of the human body?
46 chromosomes/23 pairs
Which 2 types of cells do not have chromosomes in the human body?
Sex cells and gametes.
What are chromatids?
Identical halves of a chromosome that are created when a chromosome is copied in preparation for cell division.
What are genes?
The basic units of heredity and are made up of DNA.
What are genes responsible for?
The characteristics of an organism.
What are the 2 types of genes?
Structural genes and regulatory genes.
What are structural genes responsible for?
They are responsible for the physical traits of an organism. EXAMPLE: hair color and eye color are determined by structural genes.
What do regulatory genes do?
They control the activity of other genes. EXAMPLE: regulatory genes can turn other genes on or off.
What does DNA stand for?
Deoxyribonucleic acid
What is DNA made up of?
2 long chains of nucleotides that twist to create a double helix
The building blocks of DNA are ____.
Nucleotides
The sequence of the nucleotides in DNA determines the order of ____ in ____. What is this known as?
Amino acids, proteins. The genetic code.
How many bases do the nucleotides in DNA have? What are they?
- A (adenine), T (thymine), G (guanine), and C (cytosine).
What are base pairs (regarding DNA)?
2 nucleotides that are bonded together with hydrogen bonds. EXAMPLE: A = T and C = G (think ATV and CGI to remember which ones bond with which) (can also think Apple in Tree and Car in the Garage).
The nucleotide bases of DNA are held together with ____.
Hydrogen bonds
What is the relationship between DNA, genes, and chromosomes within the context of heredity?
Chromosomes are composed of DNA, and genes are specific segments of chromosomes that dictate individual traits.
Chromosomes are long strands of ____ wrapped around proteins called ____.
DNA, histones
Genes are segments of ___ which are located on the ____.
DNA, chromosomes
What is a codon?
A sequence of 3 nucleotides that code for a specific amino acid.
The genetic code is read in groups of 3 nucleotides called ____.
Codons
How many total possible codons are there? How many are codon codes and how many are “stop signal” codons?
- 61 and 3.
What does RNA stand for?
Ribonucleic acid
What is the principal role of RNA?
To translate the genetic code of DNA into proteins.
RNA is very similar to DNA except for what 2 key differences?
RNA is single-stranded whereas DNA is double-stranded. RNA also has the base uracil (U) whereas DNA has the base thymine (T).
DNA is present ____ the nucleus whereas RNA is present ____ and ____ the nucleus.
Inside, inside and outside.
How many bases do the nucleotides of RNA have? What are they?
- A (adenine), U (uracil), C (cytosine), and G (guanine).
What are the base pairs (regarding RNA)?
A = U and C = G. (a way to remember the pairs is Apple Under the tree and Car in the Garage).
What 2 functions do DNA and RNA perform?
Transcription and translation.
What is transcription (regarding DNA)?
The process of making RNA from DNA. The DNA’s double-helix unwinds, and one strand of the DNA serves as the template for RNA.
What is RNA polymerase?
An enzyme that catalyzes the formation of RNA from nucleotides. This enzyme attaches to one end of the DNA template and then moves along the template, adding nucleotides ones at a time.
RNA is found in what 3 main forms?
Messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA).
What is messenger RNA (mRNA)?
The RNA that carries the genetic code from the DNA in the nucleus to the ribosomes in the cytoplasm (in short, it carries genetic information to make proteins).
What is transfer RNA (tRNA)?
The RNA that helps to assemble amino acids into proteins that act as adapters in the translation of the genetic sequence (in short, it’s an adapter molecule that decodes a mRNA into a protein).
What is ribosomal RNA (rRNA)?
The RNA that makes up ribosomes. It serves as a location for protein synthesis.
What is transcription (regarding DNA)?
The process of making an RNA copy of a gene’s DNA sequence.
What is translation (regarding DNA)?
The process of making proteins from RNA.
Where does translation (regarding DNA) occur?
On the ribosomes in the cytoplasm.
How does translation (regarding DNA) occur?
mRNA attaches to the small subunit of a ribosome and then tRNA brings amino acids to the ribosome. As the amino acids are brought to the ribosomes, they are joined together by peptide bonds to form a protein.
In what order does translation and transcription occur?
Transcription comes before translation. (C comes before L)
Which component is essential for initiating the transcription of a gene into mRNA in eukaryote cells?
RNA polymerase
What is the role of mRNA in protein synthesis?
It serves as a template for assembling amino acids into proteins.
What is inheritance (regarding traits)?
The process by which traits are passed from parents to their offspring.
What is Mendel’s law of inheritance?
It states that there are 2 alleles for each trait.
What are alleles?
Alleles are alternative forms of a gene.
One allele is ____ and the other allele is ____.
Dominant, recessive
The allele that is expressed in the phenotype is the ____.
Dominant allele
How many alleles does each parent contribute to their offspring?
1
What is the combination of 2 alleles called?
Genotype
What is a phenotype?
An individual’s observable traits produced by the interaction of the genotype, such as height eye color, and blood types.
If the chromosome contains 2 different alleles for a trait, then the genotype is ____.
Heterozygous
If the chromosome contains 2 identical alleles for a trait, then the genotype is ____.
Homozygous
What is incomplete dominance regarding exceptions of Mendel’s law of inheritance?
The phenotype of the offspring is a blend of the phenotypes of the parents. EXAMPLE: if a red flower (RR) is crossed with a white flower (WW), the offspring with be pink (RW).
What is codominance regarding exceptions of Mendel’s law of inheritance?
The phenotype of the offspring is a combination of the phenotypes of the parents. EXAMPLE: if a black chicken (BB) is crossed with a white chicken (WW), the offspring will be black and white (BW).
What are macromolecules?
Large molecules that are essential for the structure and function of cells.
What is a monomer?
It’s a building block. It’s a molecule that can react together with other monomers to form a larger polymer chain.
What is a polymer?
A macromolecule that is made up of smaller units called covalent bond-linked monomers.
What is the chemical reaction dehydration synthesis?
The formation of larger molecules from smaller reactants accompanied by the loss of a water molecule.
What is the chemical reaction hydrolysis?
The process of breaking down bonds to break monomers.
What are the 4 major types of macromolecules?
Carbohydrates, lipids, proteins, and nucleic acids.
What is the monomer of carbohydrates?
Monosaccharides
What are carbohydrates? What are they also known as?
Biomolecules composed of carbon, hydrogen, and oxygen. They are also known as “sugars” or “starches” found in all living organisms.
The carbohydrate rule: the word ends in ____.
-ose
What are the 3 types of carbohydrates?
Monosaccharides, disaccharides, and polysaccharides.
What are monosaccharides?
They are the simplest type of carbohydrate. They cannot be hydrolyzed to produce smaller units.
What is a common monosaccharide?
Glucose
What are disaccharides?
2 monosaccharides that are joined together by a covalent bond.
What is a common disaccharide?
Sucrose (table sugar)
What are polysaccharides?
Long chains of monosaccharides that are joined by covalent bonds.
What are 2 common polysaccharides?
Starch and cellulose.
Carbohydrates can also take many different forms to perform functions. These forms can be ____, ____, and ____.
Linear, branches, helix-shaped.
What are linear carbohydrates?
Long unbranched chains of monosaccharides that form structures.
What are branched carbohydrates?
Shorter chains of monosaccharides with branches.
What are helix-shaped carbohydrates?
Coiled chains of monosaccharides that form structures.
What are lipids composed of?
Carbon, hydrogen, and oxygen.
What is the monomer of lipids?
They don’t have a true monomer.
What are lipids important for?
They are important for energy storage, structural, and hormonal macromolecules.
How are lipids formed?
By a linear arrangement of carbon atoms and hydrogen atoms called fatty acid chains.
What 4 groups can lipids be divided into?
Fats and oils, waxes, phospholipids, and steroids.
Are lipids hydrophobic or hydrophilic to water?
Hydrophobic
Are lipids polar or non-polar to water?
Non-polar
Are the 4 groups of lipids soluble or insoluble to water?
Insoluble
What are fat molecules composed of?
A glycerol molecule and 3 fatty acid chains.
What are fats used for?
Long-term energy storage in the body.
What type of lipid is primarily used by the body for long-term energy storage?
Triglycerides
What are waxes composed of?
A long chain of fatty acids that are linked to long-chain alcohol.
What are phospholipids composed of?
A glycerol molecule, 2 fatty acid chains, and a phosphate group.
Phospholipids are a major component of ____.
Cell membranes
What are steroids composed of?
4 interconnected carbon rings.
Steroids include ____, which is a structural component of ____, and ____ like testosterone and estrogen.
Cholesterol, cell membranes, hormones.
What are proteins composed of?
Carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur.
What is the monomer of proteins?
Amino acids
Proteins are made up of smaller units called ____ that are linked together by ____.
Amino acids, peptide bonds.
What 4 groups can proteins be classified as?
Enzymes, structural proteins, storage proteins, and transport proteins.
What are enzymes?
Proteins that catalyze biochemical reactions without being consumed by the reaction. They speed up reactions by lowering the energy required to initiate the reaction.
An ____ reaction releases energy.
Exergonic
An ____ reaction requires energy.
Endogenic
What do structural proteins provide?
Support and structure.
What do storage proteins store?
Nutrients
What do transport proteins transport?
Molecules
What are nucleic acids composed of?
Carbon, hydrogen, oxygen, nitrogen, and phosphorus.
What is the monomer of nucleic acids?
Nucleotide
What do nucleic acids do?
Store and transmit genetic information.
What are the 2 types of nucleic acids?
RNA and DNA
Which type of macromolecule plays a key role in forming cellular membranes?
Lipids (specifically phospholipids).
What are micro-organisms? What are they also known as.
Tiny living organisms. Microbes
Micro-organisms can only be seen with a ____.
Microscope
What does pathogenic mean?
An infectious agent capable of inducing disease.
What does virulence mean?
How severe or harmful the disease is.
What are bacteria?
Single-celled micro-organisms that can live in many different environments. Some bacteria cause diseases.
Bacteria lacks a ____ which makes them a ____.
Nucleus, prokaryote.
What are viruses?
They are even smaller than bacteria and can only be seen with an electron microscope. They are not considered to be alive because they cannot reproduce on their own.
Viruses must infect a ____ in order to ____.
Host cell, reproduce.
What are characteristics of a virus?
o Not a cell
o Not alive
o Needs to reside in a host cell to function
o The outside covering is called capsid
o The genetic core inside is referred as a genome (RNA/DNA)
o Envelope
What are protozoans?
Single-celled micro-organisms that are found in water, soil, and air. Some cause diseases.
What are fungi?
Micro-organisms that are classified as eukaryotes. Some are helpful, some cause diseases.
What are the characteristics of fungi?
o Cell wall made of chitin
o Can reproduce sexually or asexually with spores.
What are animals in terms of micro-organisms? Also called ____.
Parasitic worms, flatworms, and roundworms. Helminths
What are prokaryotes?
Cells without a nucleus.
What are eukaryotes?
Cells with a nucleus.
What are infectious diseases?
Diseases that can be spread from one person to another. They are commonly known as communicable diseases.
What are examples of infectious diseases?
Bacteria, viruses, protozoa, and fungi such as chickenpox and COVID.
What are noninfectious diseases?
They are not caused by microorganisms and cannot spread from person to person.
What are examples of noninfectious diseases?
Cancer, heart disease, and diabetes.
What 3 ways do infectious diseases spread?
Direct contact, indirect contact, and vectors.
What is direct contact regarding infectious disease spreading?
When the infectious agent comes into contact with the mucous membranes or broken skin of another person.
What is indirect contact regarding infectious disease spreading?
When an infectious agent comes into contact with an object or surface that another person will then touch.
What are vectors regarding infectious disease spreading?
Living organisms that can carry and transmit an infectious agent to humans or other animals.
What are examples of vectors regarding infectious disease spreading?
Mosquitoes, ticks, and fleas
