Biology Flashcards
Steps of the scientific method:
- Observation: New ones are made or previous data is studied
- Hypothesis: statement or explanation of certain events or happenings
- Experiment: Repeatable procedure of gathering data to support or refute the hypothesis.
- Conclusion: Data and significance are fully explained.
A life, and therefore biology, occurs in what?
A water based/ aqueous environment.
What is the most significant aspect of water?
The polarity of its bonds that allow for hydrogen bonding between molecules.
Benefits of water’s polar covalent hydrogen bonding?
-High specific heat (hydrogen bonds allows for large bodies of water to maintain a stabile env.)
-Strong cohesive and adhesive properties
-Is one of the few solids that floats in its solid form on top of its liquid form.
- Allows water to act as a versatile solvent
Specific heat:
Amount of heat necessary to raise the temperature of 1 gram of that molecule by 1 degree Celsius.
—— is the ability of a molecule to stay bonded or attracted to another molecule of the same substance.
CO-hesion. Cohesion.
—– is the ability of water to bond to or attract other molecules or substances.
ADD-hesion. Adhesion.
Why does frozen ice float?
When water freezes it forms a lattice crystal- the molecules spread apart, thereby reducing density, rather than packing tightly together (as seen with lipids).
The 4 most significant molecules to biology:
- Carbohydrates
- Lipids.
- Proteins
- Nucleic Acids
Three most important functions of carbohydrates?
Storage
Structure: Forms the backbone of important molecules, such as DNA and RNA
Energy: Converted into ATP
Three classes of Lipids:
- Fatty Acids
- Phospholipids
- Steroids
Two classes of fatty acids:
- Saturated: No double bonds in hydrocarbon tail. Solid at room temp.
- Unsaturated: 1 or more double bonds.
Phospholipid structure:
Two fatty acids, or more, bonded to a phosphate group
Which part of the phospholipid is hydrophobic and which is hydrophilic? And why?
The phosphate group is charged = polar and soluble in water.
The hydrocarbon tail of fatty acids is nonpolar = nonsoluable in water.
Which molecule is the most significant contributor to cellular function?
Protein. (Largest of all of the biologic molecules)
—- is the sum of all chemical reactions that occur in an organism.
Metabolism
In a cell, reactions take place in a series of steps called:
Metabolic pathways.
—- is the fundamental unit of biology.
The cell.
Two types of cells:
Prokaryotic
Eukaryotic
Structure of prokaryotic cells:
Lack a defined nucleus. Do not have membrane bound organelles.
Structure of eukaryotic cells:
Membrane-enclosed nucleus; series of membrane-bound organelles that carry out the functions of the cell as directed by the genetic information contained in the nucleus.
More complex than a prokaryotic cell.
The nucleus contains the DNA of the cell in organized masses called:
Chromosomes
What information does a chromosome contain?
All of the genetic information for the regeneration (repair and replication) of the cell, as well as instructions for the function of the cell.
Every organism has a characteristic number of chromosomes specific to the particular:
species
What is the backbone of a DNA chromosome?
Nucleotide backbone made up of Deoxyribose sugar and phosphate groups. DS-P-DS-P
What are the four base pairs of DNA?
Nucleic acids:
Adenine (Pairs with Thymine)
Guanine (Pairs with Cytosine)
Two types of ribosomes and their location within the cell:
Bound ribosomes: rough endoplasmic reticulum
Free ribosomes: within the cytoplasm
Where is the ER found within the cell?
Attached to the nuclear membrane.
Function of the rough ER:
Protein synthesis; membrane production
Function of the smooth ER:
Detoxification and metabolism of multiple molecules.
Function of Golgi apparatus.
Packaging, processing, shipping
Transports proteins from the ER throughout the cell
Intracellular digestion takes place in lysosomes. What type of enzymes are within the lysosomes?
Hydrolytic enzymes (catalyzes the breakdown of molecules by reacting with water)
What do lysosomes hydrolyze?
Proteins, fats, sugars, and nucleic acids.
What is the pH within a lysosome?
4.5 (acidic)
—- is the process by which a cell uptakes food through the food membrane creating a food vacuole
Phagocytosis
Function of a plant cell vacuole?
Storage, water disposal, protection, hydrolysis
Two distinct organelles that produce cell energy:
Mitochondrion: cellular respiration
Chloroplast: photosynthesis
The makeup of the cell membrane?
-Phopholipid bilayer: phospholipids with proteins, cholesterol, and glycoproteins peppered throughout.
Two catabolic pathways that leads to cellular energy production as a simple combustion reaction:
Cellular respiration
Fermentation
What is the respiration equation?
C6H12O6 + 6O2»_space;> 6CO2 + 6H2O
A compound that acts as a reducing agent and is a vehicle of stored energy:
Reduced nicotinamide adenine dinucleotide (NADH)
What is NADH used for:
As a precursor to produce greater amounts of ATP in the final steps of respiration.
3 steps of cellular respiration:
Glycolysis
Citric acid cycle (Krebs cycle)
Electron transport chain
What is glucose converted to during glycolysis?
Pyruvate.
What are the molecules produced during glycolysis?
2 ATP
2 pyruvate
2 NADPH
Where does glycolysis take place?
Within the cytosol of the cell.
What happens after glycolysis is complete?
Pyruvate is transported into a mitochondrion and used in the first of a series of reactions: The citric acid cycle/ Krebs cycle.
Where does the citric acid cycle/ Krebs cycle take place?
Within the matrix of the mitochondria.
What molecules does a single consumed glucose molecule produce within the citric acid cycle/ Krebs cycle?
2 ATP
6 CO2
6 NADH
What does the series of steps that makes up the electron transport chain begin with?
The oxidation of NADH molecules to produce oxygen and finally water.
What molecules are produced during the electron transport chain?
For every glucose molecule consumed:
28-32 ATP
What is the total amount of ATP produced through cellular respiration?
32-36 molecules of ATP
The chemical equation for photosynthesis?
The reverse of cellular respiration:
6CO2 + 6H2O + Light energy = C6H12O6 + 6O2
Two stages of photosynthesis:
Light reactions
Calvin cycle
What are light reactions?
Conversion of solar energy to chemical energy.
Once a cell has absorbed light, what is the solar energy used for in order to convert it into chemical energy (ATP)?
The light/solar energy is used to split a water molecule, which then transfers an electron to create nicotinamide adenine dinucleotide phosphate (NADPH) and ATP.
Once the water molecule has been split, and an electron transferred to create NADPH and ATP, what are the energy molecules used to do?
They are used in the Calvin cycle to produce sugar.
Sugar produced in the Calvin cycle is polymerized and then ?
Stored as a polymer of glucose.
Who can consume plant glucose to produce energy by cellular respiration?
Both organisms and plants themselves.
What are the raw materials needed for cellular respiration?
Glucose and oxygen
What are the products of cellular respiration?
Water, carbon dioxide, and ATP
What are the raw materials used by plants and autotrophs in the process of photosynthesis?
Water, and carbon dioxide.
What are the products of photosynthesis?
Oxygen & glucose
Cells reproduce by how many different processes?
3
All three processes of cell reproduction fall into two categories:
Sexual
Asexual
Two types of asexual reproduction:
-Binary fission
-Mitosis
Process of binary fission (as used by bacterial cells):
Chromosomes bind to plasma membrane, where it replicates. The cell grows and pinches into two identical daughter cells.
Mitosis occurs in how many stages?
5
What are the 5 stages of mitosis?
- Prophase
- Prometaphase
- Metaphase
- Anaphase
- Telophase
In which stage are the chromosomes visibly separate, with each duplicated chromosome having two sister chromatids?
Prophase
In which mitotic phase does the nuclear envelope begin to disappear, and the chromosomes begin to attach to the spindle that is forming along the axis of the cell?
Prometaphase
What mitotic phase shows chromosomes aligning along the center of the cell?
Metaphase
Where chromosomes align in the center of the cell during metaphase of mitosis, what is the center of the cell called?
Metaphase plate
What phase of mitosis begins when chromosomes start to separate?
Anaphase
In anaphase of mitosis, what are the chromatids considered to be?
Separate chromosomes.
What is the final phase of mitosis, in which chromosomes gather on either side of the separating cell?
Telophase
What is the second process associated with cell division after the 5 stages of mitosis is complete?
Cytokinesis: when the sell pinches into two forming two separate identical cells.
Two stages of meiosis:
Meiosis 1 and meiosis II
How many daughter cells are present after meiosis?
4
How many chromosomes are in a daughter cell after meiosis?
23.
Preceding meiosis 1 and meiosis 2 is what period?
Interphase
What occurs during interphase?
Chromosomes are duplicated and the cell prepares for division
What is another name of meiosis?
Reduction division (as in their is only 23 chromosomes within sex cells such as a sperm and an egg)
Four phases of meiosis I:
-Prophase 1
-Metaphase 1
-Anaphase 1
-Telophase
Followed by cytokinesis
What phase do significant differences between meiosis and mitosis occur?
Prophase 1. The three following stages are the same as mitosis. Miosis 2 is identical to mitosis, except the chromosome pairs separates, resulting in 4 daughter cells with 23 chromosomes (rather than 46.
During which phase of meiosis 1 do nonsister chromatids of homologous chromosomes cross at numerous locations?
Prophase 1
Who discovered the basic principles of genetics using garden peas?
Gregor Mendel
How many alternative versions of genes exists for each trait?
2: “alleles”
Simple traits have versions that can be one of two types:
Dominant or recessive
If a dominant allele is present, then what will be expressed as the dominant trait?
Phenotype.
What tool predicts the genotype and phenotype of the offspring of sexual reproduction?
Punnett square
What is a genotype?
A combination of alleles.
What are the 4 other methods (of many) used to assess genetic expression?
Multiple alleles
Pleiotropy
Epistasis
Polygenic inheritance
What connects two sister chromatids?
Centromere
Which type of cellular reproduction begins with a diploid cell and ends with two diploid cells?
Mitosis.
Which type of cellular reproduction begins with a diploid cell and ends with 4 haploid cells?
Meiosis
A —– is a family tree that traces the occurrence of a certain trait through several generations.
Pedigree (can help to understand the genetic past and the possible future)
What is the genetic material of a cell and is the vehicle of inheritence?
DNA
Who described the structure of DNA in 1953?
Watson & Crick
What bonds hold nitrogenous bases together?
Hydrogen.
Each —- along a strand of DNA is a template for protein synthesis?
gene
What is the first step in DNA replication?
Transcription: mRNA strand is produced, with uracil pairing with adenine.
Where is the site of translation?
Ribosomes. (The mRNA slides through a ribosome)
Every group of three bases along the stretch of RNA is called a —-
codon: codes for a specific amino acid
Where is the anticodon located?
transfer RNA (tRNA)- carries a specific amino acid.
How does tRNA attach amino acids to create a protein?
tRNA carries a specific amino acid to the ribosome and binds to the ribosome when its codon is sliding through the ribosome. Each amino acid is bonded together and released by the preceding tRNA molecule.
What signals the end of an amino acid chain being translated?
Stop codon.
What happens once the chain of amino acids is released into the cytoplasm?
The protein folds onto itself and forms its complete conformation.
Where does mRNA leave the nucleus?
Through the large nuclear pores.
What are the bonds that are formed between amino acids?
Peptide bonds: polypeptides.
In the scientific process, which of the following is a statement or explanation of certain events or happenings?
A. Hypothesis
B. Observation
C. Experiment
D. Conclusion
A. Hypothesis
Why is polarity the most important characteristic of water?
A. The results of polarity are hydrogen bonding, a high specific heat value, and its versatile solvent properties.
Which organelle would you expect to be present in a cell responsible for detoxifying multiple molecules?
A. Rough endoplasmic reticulum
B. Smooth endoplasmic reticulum
C. Lysosome
D. Golgi apparatus
B. Smooth endoplasmic reticulum
A cell from heart muscle would more than likely contain an unusually high proportion of:
A. lysosomes
B. mitochondria
C. mRNA
D. ribosomes
B. Mitochondria
The sum of all chemical reactions that occur in an organism is:
A. Product
B. Respiration
C. Metabolism
D. Synthesis
C. Metabolism
What is the relationship between sarcomeres, myofibrils, and muscle cells?
Muscle cells contain myofibrils, which in turn are made up of sarcomeres.
Muscle cells, like erythrocytes or nerve cells have distinct structures when being compared to the classical “cell” studied” (e.g. epithelial, cuboidal, columnar, etc.)
Muscle cells have long fibers (myofibrils) filled with sarcomeres (the smallest functional unit of the muscle). Sarcomeres are what each contracts causing the muscle to shorten. The sarcomere is what contains actin and myosin.
Which level of protein structure refers to the association of the various subunits of a multi-subunited protein into a three-dimensional functional protein?
A. primary
B. secondary
C. tertiary
D. quaternary
D. quaternary
Primary structure = chain of amino acids
Secondary structures: coiling by hydrogen bonding forming:
a- helices
B- sheets
Tertiary structures: Folding by R group interactions
Quaternary: two or more chains associating.
Where does capping occur on an mRNA strand and why?
On the 5’ end to prevent from degradation
During what process does hydrolysis occur to provide electrons to chlorophyll, which subsequently absorbs energy?
A. Light-dependent reactions of photosynthesis
B. Light-independent reaction of photosynthesis
C. Calvin cycle
D. Krebs cycle
A. light-dependent reaction provides electrons to chlorphyll for the calvin cycle to occur. Light-dependent reactions also release oxygen in the process.
Where is the energy provided from the dependent light reaction stored?
In chemical bonds of glucose molecules.
In photosynthesis, high-energy electrons move through electron transport chains to produce ATP and NADPH. Which of the following provides the energy to create high energy electrons?
A. NADH
B. NADP+
C. water
D. Light
D. light
Electrons are trapped by the chlorophyll P680 molecule in photosystem II. The electrons become energized by light. They are then transferred to electron acceptors in an electron transport chain.
What is the process called when root hairs capture water and move it upwards into the rest of the plant?
A. photosynthesis
B. diffusion
C. active transport
D. transpiration
D. transpiration
Moves up a plants conduction tubes against the force of gravity
Which plant hormone causes fruit to ripen?
A. auxins
B. cytokinins
C. ethylene
D. abscisic acid
C. Ethylene
What do auxins and cytokinins do?
Promote cell growth.
Auxins encourage stem elongation and can inhibit growth of lateral branches.
What does abscisic acid do?
Inhibits cell growth and seed germination
What is thigmotropism?
A. Growth of plant materials towards light
B. Growth of leaves and stems opposite to the pull of gravity
C. Growth toward a source of nutrition
D. Growth of plant structures in response to contact with a physical structure.
D.
What word means growth towards light?
Phototropism
What words is the growth of leaves and stems opposite the force of gravity?
Gravitropism
What is the purpose of stigma?
A. to gather pollen
B. to attract pollinators like birds and bees
C. To nourish the fertilized ovum
D. to produce pollen
A. To gather pollen
Stigma is a long tube that extends from the center of a flower whose function is to gather pollen and transport it down the carpel toward the ovum.
What attracts pollinators like birds, butterflies, and bees?
The bright-colored petals of a flower.
Where is pollen produced?
In the stamen and anther: protrudes from the flower to make it easier for pollinators to gather pollen as they fly from flower to flower
What is the function of the ovary of a flower?
Provides nourishment for developing seeds
Which of the following kinds of plants is most likely to perform CAM photosynthesis?
A. Mosses
B. grasses
C. deciduous trees
D. cacti
D. cacti.
Crassulacean acid metabolism (CAM) photosynthesis occurs in plants that grow where water loss must be minimized.
They open their stomata and fix CO2 at night, while during the day the stomata is closed, reducing water loss.
What are the first life forms to colonize a new area?
Pioneer species.
What are primary producers?
They produce their own food, usually from sunlight.
What are primary consumers?
Herbivores that eat primary producers
What are secondary consumers?
Eat primary consumers
What are tertiary consumers?
Eat secondary consumers
During photosynthesis the Calvin cycle uses ATP to produce which of the following?
A. fats
B. sugar
C. carbohydrates
D. protein
Sugar
Which is the smallest type of biological molecules?
A. monomer
B. amino acids
C. nucleic acids
D. nucleotides
A. Monomer: “single component or bead”
Cells are made up of strings of monomers- the building blocks of all biomolecules.
Nucleic acids are strings of nucleotides
Proteins are strings of amino acids
Which of the following is a single cell or cytoplasmic mass containing several nuclei, formed by fusion of cells or by division of nuclei?
A. Syncytium
B. Myocardium
C. Endocardium
D. Tachytium
A. Syncytium.
EX: Development of skeletal muscle
A messenger characterizes a polymer that consists of
glycerol molecules. What does she write in her notes about this polymer?
A. These molecules will for lipid biomolecules
B. This polymer is capable of storing very little energy
C. The glycerol molecules are covalently bonded together
D. This polymer will help transmit genetic information in a cell
C. The glycerol molecules are covalently bonded together
A study was performed to evaluate which type of road salt deiced a road most quickly. What is the independent variable?
A. Deicing time period
B. Road used for deicing
C. Type of road salt used
D. Amount of road salt used
C. Type of road salt used.
The independent variable is what is changed.
Dependent variable is what is observed: deicing time period
Control: what is kept the same. Amount of salt and road used
A researcher discovers a cell that is less than 0.5 millimeters in diameter. This cell has pili surrounding its cell wall. What does the researcher classify this cell as?
A. Autotroph
B. Eukaryote
C. Heterotroph
D. Prokaryote
D. Prokaryote
