Biology First Quarter Flashcards
Cells
The smallest unit of life.
Atoms
The smallest part of an element
Elements
A substance that cannot be broken down into simpler substances by normal chemical means
Molecules
Two or more atoms bonded together
Covalent bonding
When two atoms share an electron
The octet rule
Atoms are most stable when their outer shell is filled to the max (eight) with electrons. Atoms will bond to try to accomplish this.
Ionic bonding
When an atom robs one or more electron from another atom. Since the robber becomes negatively charged (it’s gained an extra electron) and the robbed becomes positively charged (it lost an electron) the two stick together
Atomic number
The number of protons in an atom (i.e. if the atomic number of an atom is 6, it is carbon)
The three parts of an atom
Protons, electrons, and neutrons
Protons
The positively charged part of the nucleus of an atom
Neutron
Part of the nucleus of an atom; has no charge
Electrons
Have a negative charge and orbit the nucleus
Atomic weight (or mass)
The number of protons and neutrons in an atom (i.e. if it is carbon, the atomic weight is 12, six protons and six neutrons)
Isotopes
each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei, and hence differ in relative atomic mass but not in chemical properties; in particular, a radioactive form of an element
Shells of an atom
The part of an atom where the electrons move around
Orbitals
They hold the electrons. A maximum of two electrons can fit in one orbital. There can be one or more orbitals per shell. The first shell contains one orbital (two electrons), and the second and third shell contain four orbitals (eight electrons).
Hydrogen Bonding
a weak bond between two molecules resulting from an electrostatic attraction between a proton in one molecule and an electronegative atom in the other.
Polar bonding
When the electrons are not evenly distributed, causing a slight charge
Non-polar bonding
When the molecules are evenly distributed, causing a neutral charge
Acid
A substance that gives off hydrogen atoms
Chemical reaction
when atoms come together to make a molecule, or when a molecule breaks up into separate atoms
Reactants
The atoms that come together to form a molecule in a chemical reaction
Product
The molecule that results from reactants coming together
The laws of thermodynamics
- Matter cannot be created or destroyed
2. Given enough time, everything wears out and and falls apart
Carbohydrates
A compound of carbon, hydrogen, and oxygen
Saccharides
Sugar. Monosaccharides: simple sugar. Disaccharides: two monosaccharides bonded together. Polysaccharides: many monosaccharides bonded together.
Lipids
Things like wax, fat, and steroids; usually don’t mix with water; provide insulation to cells
Steroids
Chemical messengers and also make up cholesterol which is a thin membrane on the outside of cells
Proteins
Made of amino acids. When you get many amino acids strung together, it’s a protein
Enzymes
Make chemical reactions happen faster or slower
Nucleic Acids
Found in the nucleus of a cell; made of nucleotides; have five different nitrogenous bases: adenine, thymine, cytosine, guanine, and uracil
Nucleotides
When a base, a sugar, and a phosphate group form either DNA or RNA
Organic Chemistry
A study of the common elements that make up living things and the chemical compounds produced by living things
Hydrolysis Reaction
When water is split into OH and H and placed back in their original position
Starch
A polysaccharide composed of glucose units and is primarily used as food storage in plants
Glycogen
Used in short-term food storage in animals
Cellulose
A polysaccharide that give plants their structure, is the main component of the cell wall
Phospholipids
Similar to a diglyceride (a glycerol plus two fatty acids) but it has a molecular group with a positive and negative charge hanging off the third carbon. The fatty acids are water-repelling, but the charged part of the phospholipid is water-friendly. It has a water-loving head (hydrophilic), and a water-fearing tail (hydrophobic)
Two people who developed microscopes
Robert Hooke and Antony van Leeuwenhoek
The cell theory
- Cells use and transfer energy
- Hereditary information is passed from cell to cell
- All cells have the same basic chemical composition
Cell principles
- All living things are made of at least one cell
- A cell is the basic unit of organization
- All cells come from pre-existing cells
Two different kinds of cells
Prokaryotic–single celled organisms, and Eukaryotic–multicellular organisms
Plasma membrane or cell membrane
The outer boundary that separates the cell from its environment; responsible for maintaining homeostasis; some molecules can come into the cell, but some are forced to stay out; made of a phospholipid bilayer
Cytoplasm
Fluid inside the cell; contains molecules and organelles; contains a network of fibers that give the cell its shape
Organelles
“Little organs” inside the cell
Nucleus
The “control center” of the cell, containing all the DNA, the genetic material, of the cell; inside it is the nucleoplasm, and outside it is the nucleic envelope
Passive transport
No energy is needed to move molecules from a high concentration to a lower concentration (diffusion)
Active transport
Using energy to move molecules from a lower concentration to a higher concentration
Endocytosis
A form of active transport; the cell forms a bubble around the molecules and brings it into the cell
Exocytosis
Movement outside of the cell
Ribosomes
Made inside of the nucleus, made of proteins and RNA. They work to line up amino acids to make proteins. They either float freely in the cytoplasm or are attached to the endoplasmic reticulum
Endoplasmic Reticulum
Rough endoplasmic reticulum: has ribosomes attached to it, produces proteins
Smooth endoplasmic reticulum: responsible for making lipids, sometimes detoxifies the cell, the proteins it makes are tagged and sent to the Golgi apparatus
Golgi apparatus
Serves as the shipping center of the cell. It sorts the proteins made in the rER into vesicles. Some proteins are sent to Lysosomes
Lysosomes
Serve as the recycling center of the cell, contain enzymes that break down molecules
Mitochondria
Power plants of the cell, create energy through cellular respiration, take oxygen and food and turn them into CO2, water, and ATP
Chloroplasts
Only found in plants and algae, take in sunlight and turn it into energy
Vacules
Storage containers
Photosynthesis
The process by which autotrophs absorb energy from the sun and convert it to stored chemical energy. Plants need sunlight, water, and air for photosynthesis
Chlorophyll
A green pigment responsible for absorbing light, found in clusters in the thylakoid membrane
Light dependent phase
The first phase of photosynthesis where plants convert energy from the sunlight into ATP; molecules called photosystems absorb energy from the sun, and that energy splits water molecules into H and O molecules. The remaining H+ ions and electrons are passed along an electron transport chain. This results in ATP and NADPH, an electron carrier
Calvin Cycle
The process by which plants produce glucose for food, occurs in the stroma. A molecule of CO2 from the air diffuses into the cell. It binds to a five-carbon sugar (ribulose biphosphate) making a 6 carbon molecule. It splits into two molecules (3 each). ATP gives energy and NADPH contributes hydrogen to turn the 3 carbon molecules into 3 carbon sugars called G3P. There are 6 assembly lines of this happening at once. One of the G3Ps bonds back together with another, creating glucose, and leaves the assembly line. We divide the 30 carbons left by 6 and get 5 carbons each, enough for each assembly line to go through this process again
Cellular respiration
The process by which cells take glucose and turn it into usable energy
ATP
The chemical energy all cells need to thrive. It is produced in the mitochondria of a cell, along with CO2 and water made from oxygen and lipids or carbohydrates. It is a very unstable molecule
Aerobic respiration
When cells use glucose and oxygen to produce energy.
Four parts–glycolysis (occurs in the cytoplasm), pyruvate oxidation (occurs in the mitochondria), Krebs cycle, and oxidative phosphorylation (occurs in the inner membrane of the mitochondria.) 1 molecule of glucose yields 38 molecules of ATP
Lactic acid fermentation
A type of anaerobic cellular respiration
Anaerobic cellular respiration
Producing energy without using oxygen. If no energy is available, the cell goes through fermentation until energy is available
Cellular metabolism
Chemical reactions which include breaking food down for energy and then using that energy to build up the organism
Catabolic process
A series of pathways where molecules are broken down into smaller bits and energy is released
Protein synthesis
- DNA replication
- RNA transcription
- Protein translation
DNA
Is in the shape of a double helix; made of nucleotides; the legs of the ladder are made of the sugars and phosphate groups, and the rungs of the ladder are made of the bases: adenine and thymine, or cytosine and guanine
Genome
The complete collection of a cell’s DNA genetic material
Gene
A segment of DNA that codes for a specific protein or specific strand of RNA
Histones
DNA is wrapped around several proteins called histones which package up DNA more compactly
Chromatin
The complex of DNA and histones
Chromosomes
Coils of DNA bundled together into organized structures; chromosomes are organized into pairs and are called homologous chromosomes.
DNA replication
when cells divide, the DNA replicates so each cell can have its own copy of DNA. The enzyme helicase unzips the double helix of DNA, separating each base pair. The enzyme DNA polymerase recognizes the nitrogen bases and adds the missing ones to each side of the unzipped DNA to create two complete strand of DNA
RNA
A nucleic acid like DNA, but is single-stranded, contains a different sugar than DNA, and has uracil instead of thymine as a base pair
RNA transcription
The segment of DNA that’s needed is located, that segment of DNA is untwisted and unzipped to expose the base pairs. RNA is made by connecting the correct nitrogen bases (uracil w/ adenine and guanine w/ cytosine) to the half-strand of DNA. After the copy is made, the RNA is unzipped from the DNA. The DNA zips back together to its original shape. This RNA is called messenger RNA.
Protein translation
mRNA from transcription is transferred out of the cell’s nucleus to a ribosome which is the location of the protein translation. Part of the ribosome is another kind of RNA called rRNA. rRNA’s job is to move the mRNA along as protein translation takes place. A third type of RNA called transfer RNA assists in protein translation by transferring amino acids from other places in the cell to ribosomes
mRNA
The working copy of the DNA, determines the specific sequence of amino acids
tRNA
Brings amino acids to the sequence, and they are linked together through a special chemical reaction; continues to bring amino acids until the protein reaches a STOP codon, signaling the protein is complete
Interphase
Where all the normal cellular activities occur. There are three phases: G1 (cell growth), S (DNA replication), and G2 (more growth)
Mitosis
The process by which one cell divides into two daughter cells
Prophase
The duplicate DNA is packaged into chromosomes. The two identical halves of sister chromatids are bundled together into one chromosome and fastened together with a centromere. Microtubules form the mitotic spindle, which attaches to the chromosomes and directs their movements. The cell begins to dismantle the nucleolus, and the nuclear envelope disintegrates
Metaphase
All the chromosomes line up in the middle of the cell. Chromosomes attach to the mitotic spindle by the centromeres. The sister chromates appear to be repelling each other which causes an X shape
Anaphase
The sister chromatids are pulled away from each other and move to opposite ends of the cell
Telophase
Begins when the chromosomes reach the end of the mitotic spindle. A new nucleus begins to form around each set of daughter chromosomes, forming two daughter nuclei. Chromosomes begin to uncoil back into their chromatin form. The mitotic spindle breaks down. When the nuclear membrane has reformed, mitosis is complete
Cytokinesis
Occurs at the same time as telophase; the cytoplasm and organelles are split between the two daughter cells
Cleavage Furrowing
Occurs in animal cells and is caused by muscle-like fibers in the cytoskeleton which pinch the cell like a drawstring
Cell Plate Formation
A process plants use where a new cell wall is formed down the middle of the cell and splits the mother cell into two daughter cells
Zygote
A new organism is formed when the sperm cells and egg cells come together
Homologous Chromosomes
Pairs of chromosomes that contain the same type of genetic information which code for the same kinds of proteins, but they aren’t necessarily identical versions of the genes
Alleles
Different versions of the same gene
Meiosis
A type of cell division that makes sexual reproduction possible. Occurs in two phases: Meiosis 1 and Meiosis 2
Prophase 1
The first phase of meiosis. Chromatin is bundled into chromosomes. Sister chromatids along with their homologous chromosome pair bundle with them forming a tetrad, or a group of four
Metaphase 1
The second phase of meiosis. Chromosomes line up in the middle of the cell and face opposite sides as they attach to the mitotic spindle
Anaphase 1
The third phase of meiosis. The duplicated homologous pairs are separated from each other and move to opposite sides of the cell
Telophase 1
The fourth phase of meiosis. A new nucleus beings to form around the separated chromosomes, and cytokinesis begins
Prophase 2
The fifth stage of meiosis. The mitotic spindle forms and moves the chromosomes to the middle of the cell
Metaphase 2
The sixth phase of meiosis. The chromosomes line up in the middle of the cell
Anaphase 2
The seventh phase of meiosis. Sister chromatids separate making daughter chromosomes that move toward opposite sides of the cell
Telophase 2
The final phase of meiosis. The nuclear envelope forms and groups one copy of chromosomes at each end of the 2 cells. Cytokinesis splits the 2 cells into 4. Each of the 4 new cells has just 1 copy of haploid chromosomes
Gregor Mendel
The father of modern genetics
Studied heredity
Passing on physical or mental characteristics genetically from one generation to the next
Self-pollination
When a plant has both gametes and fertilizes itself
Cross-pollination
The male gamete of one plant fertilizes the female gamete of another plant
Dominant trait
A genetic trait that has a higher likelihood of being passed on to the next generation
Recessive trait
A genetic trait that is not as likely to be passed on to the next generation as the dominant
Genotype
The combination of alleles carried by an organism, all genes collectively, whether dominant or recessive . Determines the phenotype
Phenotype
What the organism actually looks like
Homozygous
When an organism has two copies of the same allele–either both dominant or both recessive
Heterozygous
When an organism has two different copies of an allele-one dominant and one recessive
The Law of Segragation
The segregation of the alleles (dom. + rec.) into the gametes of an organism is random
Monohybrid Cross
Crosses that only look at one trait of an organism
Law of Independent Assortment
Alleles of two (or more) different genes are sorted into gametes independently of one another. This law only works for genes that aren’t on the same chromosome. If two genes are on the same chromosome, they are inherited as one unit
Crossing Over
When two genes close to one another on the same chromosome trade genes
Dihybrid Cross
The type of cross that deals with 2 different pairs of traits at the same time
Incomplete Dominance
Occurs when two alleles are both expressed resulting in a blended phenotype. Example: a yellow flower and a red flower make an orange flower
Codominance
Occurs when two alleles for a gene are both expressed, but the characteristics are seen side by side
X-linked traits
Traits coded for only on the X chromosome
Carrier
An individual who doesn’t exhibit a trait but carries the gene for the trait–the trait is in the genotype but not the phenotype of the person
Polygenic Inheritance
When a single trait is controlled by multiple sets of genes
Structural genes
Responsible for coding outward appearances and inward components of a person’s cells
Regulatory genes
Code for proteins which turn genes on and off
Mutations
Errors in the genetic code
Translocation
Two not homologous chromosomes exchange info during meiosis. Occurs when broken pieces of chromosome attach to the wrong chromosome
Deletion
Occurs when a segment of a chromosome breaks off and is lost
Inversion
Occurs when a segment breaks off and reattaches in the correct place–but upside down
Point mutations
Errors in the genes
Substitution
Occurs when a nucleotide is removed and replaced with a different nucleotide (i.e. sickle cell anemia)
Addition
Occurs when an extra nucleotide is placed in the sequence causing a frameshift, when all the nucleotides in the DNA are shifted down by one. This will result in major problems (i.e. cystic fibrosis, Tay-Sachs disease)
Deletion (a point mutation)
Occurs when a nucleotide is removed from the DNA causing a frameshift
Aneuploidy Mutation
The presence of an abnormal number of chromosomes–trisomy and monosomy
Microevolution
Refers to small changes you see in a species over time
Macroevolution
Refers to the theory that massive changes take place over long periods of time, altering a species into something very different
Eugenics
To increase the type of people seen as desirable and to decrease the type of people seen as undesirable
Cloning
Genetic duplicates
Genetic engineering
When genes of an organism are changed through artificial means to alter an organism’s phenotype
