Unit 1: Introduction to Biology Flashcards
What is Biology?
The Study of Life
What are the five characteristics of life?
Growth, Reproduction, Organization, Response, and requirement of energy.
Why do scientists use the scientific method?
To answer questions about living things.
What are the steps to the scientific method?
Define the problem, Research, form a hypothesis, test your hypothesis, state your conclusions.
What should a good hypothesis look like?
a statement predicting the outcome. Written in clear, simple language. Should be testable.
What are some limitations to the scientific method?
hypothesis is too broad, poor technique or flawed experiments, atypical specimen or organism, biased thinking.
What is the study of the human body and how it functions?
Anatomy
What is polarity?
where each water molecule has a positive and negative charge on opposite sides of each other
What is a universal solvent?
where many substances can dissolve into water because of its weak magnetic bond
Does water get less dense or denser when it freezes?
less dense
Does water need energy?
yes
What is the study of matter?
Chemistry
What is the smallest unit of an element?
Cells
What are the building blocks of an element?
Atoms
What are atoms made up of?
Protons (positively charged), neutrons (no charge), and electrons. (negatively charge)
What is the center of an atom compared to protons and neutrons?
nucleus
What is the area in an atom compared to protons and neutrons?
Electron shells
What is the outermost electron shell in an atom
Valence shell
What are electrons in a valence shell?
Valence electrons
What is the Octet Rule?
Where most elements are stable with 8 electrons in their valence shell
What is an atom with a negative and positive charge?
Ion
What is the force connecting a positively charged atom with a negatively charged one?
Ionic bond
What is the force between two elements in a polar molecule?
Polar-bonding
What is non-polar bonding?
When electrons are evenly distributed among the atoms in a molecule
What is carbon?
contains six protons and electrons and can form single, double, or triple bonds with other atoms
What is a chemical reaction?
when atoms come together to make a molecule
What are atoms that come together to form a molecule in a chemical reaction?
reactant
What is the Second Law of Thermodynamics?
Law that states: given enough time, everything wears out and falls apart
What are Carbohydrates?
compounds of carbon, hydrogen, and oxygen
What do Carbohydrates give?
gives energy to living cells and provides structure to things like plants, fungi, and insects.
What are lipids?
are fats, waxes, and steroids used for energy, insulation, and protection
What do proteins contain?
amino acids (20 different kinds), peptide bonds (the force of linking amino acids), Protein (50 or more amino acids linking together)
What is an enzyme?
The type of protein that changes the rate of a chemical reaction
What are nucleic acids?
found in the nucleus of the cells and made of nucleotides, which form DNA, and RNA.
What is organic chemistry?
the study of the common elements that make up living things and the chemical compounds produced by living things
What is the smallest unit of life itself?
cell
What is the study of cells or cell biology?
Cytology
Who discovered cells?
Robert Hooke
What are the basic principles to cell theory?
all living things are composed of 1 or more cells, a cell is the basic unit of organization in all organisms, all cells come from existing cells
What are more observations about cells using the cell theory?
cells use and transfer energy, hereditary information is passed from cell to cell, all cells have the same basic chemical composition
What is the organization of cells in multicellular organisms?
1) Tissue a group of tissues connect together to carry out a function
2) Organ- several types of tissues work together to perform a function
3) Organ System- a group of organs cooperating to perform together
What is a prokaryotic cell?
single-celled organism such as bacteria or blue-green algae
What is a eukaryotic cell?
type of cells in multicellular organisms such as plants and animals
What is the structure of eukaryotic cell?
1) Plasma membrane- the outer boundary of the cells
2) Cytoplasm- fluid inside the cells
3) Organelles- little organs inside the cell
4) Nucleus-the control center of the cell
What is passive transport?
no energy is needed to transport molecules in and out of a cell
What is diffusion?
Molecules move from high concentration to lower concentration
What factors impact diffusion?
The Brownian motion-random movement of microscopic particles in a fluid; is affected by temperature, concentration, molecular size; osmosis-the solvent dilutes the solution
What is active transport
uses energy to move molecules from a lower to a higher concentration
What is endocytosis?
movement into the cell
What is the fluid that fills the space of the cell-cytosol?
Cytoplasm
What are the little organs inside the cell which interact with each other and function to keep the cell running smoothly?
organelles
What are the main organelles and what are their functions?
1) Ribosomes-smallest and most numerous organelles in the cell;
2) Endoplasmic reticulum (rough-responsible for producing proteins) (smooth- responsible for producing lipids)
3) The Golgi apparatus-the shipping center of the cell, sorts proteins made in the rough in the rough endoplasmic reticulum into vesicles
4) Lysosomes-recycling center of the cells, contain enzymes that break down molecules.
5) Mitochondria-power plant of the cell, creates energy through cellular respiration
6) Chloroplast- organelles found only in plants and algae, make energy through photosynthesis
7) Vacuoles, serves as the storage containers of the cell
What is the control center of the cell?
Nucleus
What is the structure of the nucleus
1) Nuclear envelope- membrane that separates the nucleus from the rest of the cell
2) Nucleoplasm-a watery gel-like substance inside the nucleus
3) DNA-found within the nucleoplasm and the master control center of the cell
4)Nucleolus- structures where ribosomes are made
What are autotrophs?
organisms that make their own food
What is photosynthesis?
the process by which autotrophs absorb energy from the sun and convert it to store chemical energy?
What do plants need for photosynthesis?
sunlight, water, air
What is the organelle found only in autotrophs which is responsible for photosynthesis?
Chloroplast
What are special disks in the chloroplast?
Thylakoids
What are stacks of thylakoids?
Grana
What is stroma?
the fluid-filled area around the grana?
What is a green pigment responsible for absorbing sunlight found in the thylakoid membrane?
Chlorophyll
What is the first part of photosynthesis, that is the process by which plants convert energy from sunlight into ATP?
Light-dependent phase
What is the second part of photosynthesis that produces glucose for food?
Calvin Cycle
What is cellular respiration?
the process by which cells take glucose and turn it into usable energy
What is ATP?
the chemical energy all cells need to thrive and is produced in the mitochondria. It is very unstable. It must constantly be manufactured by every living cell
What are the two forms of cellular respiration?
Aerobic-when cells use glucose and oxygen to produce energy
Anaerobic-producing energy without oxygen
How does aerobic respiration occur?
Through: glycolysis, Pyruvate oxidation, Krebs cycle, and oxidative phosphorylation
What is cellular metabolism?
chemical reactions that include the breaking down of food for energy and then use that energy to build up the organism
What is the catabolic process?
a series of pathways where molecules are broken down into smaller bits and energy is released
What is anabolism?
When organisms make compounds needed by cells
What is protein synthesis?
an anabolic process where cells combine amino acids in different ways to form protein
What is the three-part process of protein synthesis
DNA, genome, and the Central Dogma of Molecular Biology
What is the structure of DNA?
the nitrogen base: adenine, guanine, cytosine, and thymine; simple sugar; and a phosphate group
What are the rungs of the DNA made of?
the base pairs:
Adenine and thymine are always paired together and Cytosine and guanine are always paired together
What are the legs of the DNA made of?
sugar and phosphate
What are coils of DNA that are bundled up into organized structures?
chromosomes
What is the process of the Central Dogma of Molecular Biology?
DNA replication, RNA transcription, protein translation
What is DNA replication?
when cells divide and the DNA replicates so each cell can have a copy of DNA
What is the process of RNA transcription?
1) segment of DNA needed is located
2) segment is untwisted and unzipped to expose the base pairs
3) RNA is made by connecting the correct nitrogen to the half-strand of DNA
4) the RNA is unzipped from the DNA then zipped back
5)the RNA becomes mRNA (messenger RNA)
How does Protein translation work?
1) mRNA from transcription is transferred out of the cell’s structure into the cytoplasm to one of the ribosomes which is the location of protein translation
2) rRNA (ribosomal RNA) is involved, which moves the mRNA along as protein translation takes place
3) tRNA assists in protein translation by transferring amino acids from other places in the cell to the ribosomes
What is a codon?
where nucleotides in mRNA are found in triplets
What is the nucleotide sequence on tRNA?
anticodon
What are the two phases of the cell cycle?
interphase and mitotic phase
What is interphase?
where all normal cellular activities occur
What are the interphases?
1) G1: cell growth, increase in size, makes new organelles, synthesizes proteins
2) S phase: where DNA undergoes replication. Helicase breaks base pairs apart, DNA polymerase attaches new bases resulting in a duplicate set of DNA, microtubules are also replicated
3) G2 phase: continuation of growth and reorganization to prepare for mitosis
What happens during the mitosis phase?
cells divide its genetic material and cytoplasm between two daughter cells
What are the phases of the mitosis phase?
Prophase
Metaphase
Anaphase
Telophase
What are the phases functions?
Prophase: DNA is packaged into chromosomes
Metaphase: all the chromosomes line up in the middle of the cell
Anaphase: the sister chromatids are pulled away from each other
Telophase: begins when the chromosomes reach the end of the mitotic spindle
What is cell division?
occurs when the cytoplasm and organelles split between the two daughter cells. It happens at the same time as the telophase and happens in humans and animals
How do organisms reproduce?
through asexual reproduction or sexual reproduction
What is a gamete
the two come together to form a new organism and have half the number of chromosomes as other cells
What is the type of cell division that makes sexual reproduction possible?
Meiosis
INfWhat are the phases of meiosis 1?
Interphase
Prophase 1
Metaphase 1
Anaphase 1
Telophase 1
What are the Meiosis phases’ functions?
Interphase: DNA replicates
Prophase 1: chromatin is bundled into chromosomes; sister chromatids bundle with their homologous chromosome, forming a tetrad
Metaphase 1: chromosomes line up in the middle of the cell and face opposite sides as they attach to the mitotic spindle
Anaphase 1: the duplicated homologous pairs are separated from each other to move to opposite sides of the cell
Telophase 1: a new nucleus begins to form around the separated chromosomes and cytokinesis begins
What are the steps to Meiosis 2?
Phrophase 2: the mitotic spindle forms and moves the chromosomes to the middle of the cell
Metaphase 2: the chromosomes line up the middle of the cell
Anaphase 2: sister chromatids separate, making daughter chromosomes move toward opposite ends of the cell
Telophase 2: the nuclear envelope forms and groups one copy of chromosomes at each end of the 2 cells
What is cytokinesis?
a process that splits the two cells into four
Who was the father of modern genetics?
Gregor Mendel
Why did Mendel use pea plants as his experiment for testing genetics?
because they reproduce efficiently
What is a genetic trait that has a higher likelihood of being passed on to the next gen.?
dominant trait
What is a genetic trait that is not as likely to be passed on to the next gen.?
recessive trait
What are alleles?
different versions of the same genes
What is a genotype?
the combination of alleles carried by an organism
What is a phenotype?
what the organism looks like
What is it when an organism has two copies of the same allele?
homozygous
What is it when an organism has 2 different copies of an allele?
heterozygous
What is the law of segregation
the law that states that the alleles into the gametes of an organism is random
What is a simple way to depict genetic crossing and determine the probability of a specific genotype or phenotype
Punnett square
What is the law of independent assortment?
the law that explains alleles of 2 different genes are sorted into gametes independently of one another
When does incomplete dominance occur?
when 2 alleles are both expressed resulting in a blended phenotype
What is codominance?
when 2 alleles for a gene are both expressed but characteristics are seen side by side
What is a carrier?
an individual who doesn’t exhibit a trait but carries the gene for the trait
What is polygenic inheritance?
when a single trait is controlled by multiple sets of genes
What are structural genes?
responsible for coding outward appearance and inward components of a person’s cells
What are regulatory genes?
code for proteins which turn genes on and off
What are errors in the genetic code?
mutations
Where can there be errors?
1) chromosomes-translocation, deletion, inversion
2) genes-substitution, addition, deletion
3) aneuploidy- trisomy, monosomy
What means good origins?
eugenics
What is the goal of eugenics?
to increase the types of peoplee seen as desirable and decrease the population of people seen as undesirable
What is cloning?
genetic duplications
What is it when genes of organisms are changed through artificial means to alter an organism’s phenotype?
genetic engineering
