Biology Semester 2 Exam Review

Why does a multicellular organism increase in size?

Why does a multicellular organism increase in size?

Cells become larger and divide so that they can move nutrients/wastes across the cell membrane and keep their DNA, which splits/replicates in the process.

Why are the cells that are divided called daughter cells?

They are capable of further division/reproduction.

Prophase

DNA in nucleus condenses to form chromosomes; mitotic spindle forms; nuclear membrane dissolves

Metaphase

Chromosomes detach from spindle fibers and move to the center; chromosomes are now lined up in the middle of the cell

Anaphase

Sister chromatids are pulled apart to opposite sides of the cell by spindle fibers

Telophase

Sister chromatids at opposite ends; spindle disassembles; nuclear membrane reforms around sister chromatids, forming new nuclei

Cytokinesis

Cytoplasm divides; division of cell into two identical daughter cells

Cyclin

A protein that regulates the cell cycle.

Cancer

A disorder in which some of the body's own cells lose the ability to control growth.

What are the reactants and products of matter in photosynthesis?

They are sunlight, water, oxygen, and glucose.

How does energy change form during photosynthesis?

Sunlight combines carbon dioxide and water, which makes glucose.

Does any matter from the sun end up in plants?

No, sunlight is an energy and not a material.

What does the sun contribute to photosynthesis?

The energy to combine carbon dioxide and water to make glucose.

What can plants do that no other organism can?

They can photosynthesize to get their food that they can grow.

Photosynthesis

The process in which a plant takes in sunlight and water and converts it into glucose and oxygen.

Photosynthesis Equation

6CO₂+6H₂O = C₆H₁₂O₆+6O₂

Cellular Respiration Equation

C₆H₁₂O₆+6O₂ = 6CO₂+6H₂O

Autotrophs

Plants that make their own food.

Heterotrophs

Organisms that obtain energy from the foods they consume.

ATP

A chemical compound that cells use to store and release energy.

Why are light and chlorophyll needed for photosynthesis?

The chlorophyll absorbs energy from sunlight, which powers the whole photosynthesis operation.

Describe the relationship between chlorophyll and the color of plants.

The chlorophyll absorbs blue and red light and reflects green light, which gives the plant its color.

Thylakoids

Chloroplasts containing saclike photosynthetic membranes.

Photosystems

Proteins in the thylakoid membrane organize chlorophyll and other pigments into clusters known as this.

Stroma

The region outside the thylakoid membrane.

NADP+

A carrier molecule that accepts and holds two high-energy electrons along with a hydrogen ion.

Light-Dependant Reactions

These use energy from light to produce ATP and NADPH.

ATP Synthase

A protein in the cell membrane that spans the membrane and allows H+ ions to pass through it.

Calvin Cycle

During this, plants use the energy that ATP and NADPH contain to build high-energy compounds that can be stored for a long time.

What reactions make up the Calvin cycle?

The Calvin cycle uses ATP and NADPH from the light-dependent reaction to produce high-energy sugars.

How is light energy converted to chemical energy during photosynthesis?

When a photochemically activated chlorophyll molecule of the photosynthetic reaction center loses an electron through an oxidation reaction, light energy is transformed into chemical energy.

What is the function of NADPH?

It carries high-energy electrons by light absorption to chemical reactions.

Why are light-dependant reactions important to the Calvin cycle?

The Calvin cycle needs these reactions in order to produce high-energy sugars.

Where does photosynthesis occur?

Photosynthesis takes place in the chloroplast.

Organic

Must contain chemical energy.

What are the reactants and products of matter?

Carbon dioxide, water (reactants), glucose, and oxygen (products).

What are the reactants and products of energy?

Light energy (reactants) and chemical energy (products).

Cellular Respiration

The process that releases energy by breaking down food molecules in the presence of the oxygen.

What are the reactants of cellular respiration?

Glucose and oxygen

What are the products of cellular respiration?

Carbon dioxide and water

Where does cellular respiration occur?

Cellular respiration takes place in the mitochondria.

calorie

The amount of energy needed to raise the temperature of 1 gram of water 1 degree Celsius.

Calorie

A kilocalorie, or 1000 calories.

Glycolysis

The first step in releasing the energy of glucose, in which a molecule of glucose is broken into two molecules of pyruvic acid, a 3-carbon compound.

NAD+

Electron carrier involved in glycolysis.

Fermentation

Process by which cells release energy in the absence of oxygen.

Anaerobic

Process that does not require oxygen.

What are the products of glycolysis?

Two molecules of pyruvic acid, a 3-carbon compound.

How and why does bread rise with yeast?

The yeast eats the sugar in the flour and excretes carbon dioxide. When it releases carbon dioxide, the bubbles make it rise. This whole process is called fermentation.

Genetics

The scientific study of heredity.

Fertilization

Process in sexual reproduction in which male and female reproductive cells join to form a new cell.

True-Breeding

Used to describe organisms that produce offspring identical to themselves if allowed to self-pollinate.

Trait

A specific characteristic that varies from one individual to another.

Hybrid

The offspring of crosses between parents with different traits.

Gene

Sequence of DNA that codes for a protein and thus determines a trait.

Allele

The different forms of a gene.

Segregation

Separation of alleles during gamete formation.

Gametes

Specialized cells involved in sexual reproduction.

Gregor Mendel

An Australian monk involved in the study of genetics.

Probablity

The likelihood that a particular event will occur.

Punnett Square

The gene combination that might result from a genetic cross can be determined from this diagram.

Homozygous

Organisms that have two identical alleles for a particular trait (TT or tt).

Heterozygous

Organisms that have two different alleles for the same trait (Tt).

Phenotype

Physical characteristics of an organism.

Genotype

Genetic makeup of an organism.

Homologous

Chromosomes that each have a corresponding chromosome from the opposite-sex parent.

Diploid

A cell that contains both sets of homologous chromosomes.

Haploid

A cell that contains only a single set of chromosomes.

Meiosis

A process of reduction division in which the number of chromosomes per cell is cut in half through the separation of homologous chromosomes in a diploid cell.

Tetrad

A structure containing four chromatids that form during meiosis.

Crossing-Over

Process in which homologous chromosomes exchange portions of their chromatids during meiosis.

Interphase I

Cells undergo a round of DNA replication, forming duplicate chromosomes.

Prophase I

Each chromosome pairs with its corresponding homologous chromosome to form a tetrad.

Metaphase I

Spindle fibers attach to the chromosomes.

Anaphase I

The fibers pull the homologous chromosomes toward opposite ends of the cell.

Telophase I and Cytokinesis

Nuclear membranes form. The cell separates into two cells.

Prophase II

Meiosis I results in two haploid daughter cells, each with half the number of chromosomes as the original cell.

Metaphase II

The chromosomes line up in a similar way to the metaphase stage of mitosis.

Anaphase II

The sister chromatids separate and move toward opposite ends of the cell.

Telophase II and Cytokinesis

Meiosis II results in four haploid daughter cells.

When does variation occur during meiosis?

When the chromosomes line up for the first time.

Why is DNA complementary vs. identical?

In order for the two strands of DNA to pair together, each base must come together with its un-identical opposite.

DNA Replication

The process of copying DNA.

Semiconservative

One strand of DNA is kept the same and a new strand is added on.

Enzymes

Active proteins and the stars of DNA.

Helicase

Responsible for separating the two strands of DNA.

DNA Polymerase

Responsible for adding on new nucleotides.

Replication Bubbles

The places where replication occurs simultaneously along the DNA strand.

Antiparallel

DNA molecules run parallel but go in opposite directions.

Leading Strand

DNA polymerase continually makes this strand.

Lagging Strand

DNA polymerase makes this strand in sections called Okazaki Fragments.

Polymers of Nucleic Acids

DNA and RNA

Monomer of Nucleic Acids

Nucleotides

What are the structural differences between DNA and RNA?

They have different bases (Uracil/Thymine) and they have different sugars (deoxyribose/ribose).

What are the parts of a nucleotide?

Phosphate, Sugar, Nitrogenous Base

What is the name of the type of bond that connects the two base-pairs in a DNA molecule?

Hydrogen Bond

DNA is called ___________ nucleic acid, named after the type of sugar in the backbone.

Deoxyribo

Messenger RNA (mRNA)

RNA molecules that carry copies of instructions for assembling amino acids into proteins.

Ribosomal RNA (rRNA)

This makes up the major part of ribosomes.

Transfer RNA (tRNA)

RNA molecules that transfer each amino acid to the ribosome as it is specified by coded messages in mRNA.