biology

Biology 

Chapter 1:

Know the difference between:

a) Independent variable The variable that is changed or controlled in an experiment to test its effects on the dependent variable.

b) Dependent variable The variable being tested and measured in an experiment.

c) Control The part of the experiment that remains constant and is used as a baseline for comparison.

d) Be able to design an experiment: 

1. Identify the problem/question.

2. Form a hypothesis.

3. Define variables (independent, dependent, control).

4. Plan the method and materials.

5. Conduct the experiment.

6. Collect and analyze data.

7. Conclude and report results.

Chapter 2:

1. What is the difference between an atom, element and compound?

Atom: Smallest unit of matter.

Element: A pure substance made of only one type of atom.

Compound: A substance made of two or more elements chemically bonded.

2. Explain the difference between a monomer and a polymer.

Monomer: A single molecule that can bond with others to form a polymer.

Polymer: A large molecule made of repeated monomer units.

3. How is a Hydrogen bond formed?

 Formed between a hydrogen atom in one molecule and a highly electronegative atom (like oxygen or nitrogen) in another.

4. What is special about Hydrogen bond?

- Adhesion: Attraction between molecules of different substances.

-Cohesion: Attraction between molecules of the same substance.

-High specific heat: Ability to absorb and retain heat

5. What does the pH scale measure and what does it mean if something has a pH of 12?

Measures how acidic or basic a solution is.

A pH of 12 indicates a basic (alkaline) solution.

6. Know the characteristics of the following macromolecules:

7. Understand how enzymes are denatured.

Denaturing: Changes in temperature, pH, or salinity can alter the shape of enzymes, preventing them from working.

8. What is Activation energy?

The minimum energy required for a reaction to start.

9. What do enzymes do?

Speed up reactions by lowering activation energy.

10. Explain how enzymes act on substrates:

Substrates bind to the enzyme's active site, the reaction occurs, and the product is released.

Chapter 3:

1. List 3 differences between Prokaryotic and Eukaryotic cells:

Prokaryotic: No nucleus, smaller, simple structure.

Eukaryotic: Has a nucleus, larger, complex structure.

Prokaryotes lack membrane-bound organelles, eukaryotes have them.

2. Draw a cell and Label the following:

-Nucleus, ER, Ribosome, Golgi apparatus, Vesicles, Mitochondria, Centrosome.

-For each add a quick description of what they do.

Nucleus: Stores DNA.

Endoplasmic Reticulum (ER): Protein and lipid synthesis.

Ribosome: Protein synthesis.

Golgi Apparatus: Modifies and packages proteins.

Vesicles: Transport substances.

Mitochondria: Energy production.

Centrosome: Organizes microtubules.

3. What is the cell membrane made of? Explain why it is important for it to be selectively permeable:

Made of a phospholipid bilayer.

Selectively permeable to regulate the movement of substances.

4. Understand the difference between Hypotonic, hypertonic and Isotonic solutions:

Hypotonic: Water enters the cell (swelling).

Hypertonic: Water exits the cell (shrinking).

Isotonic: No net water movement.

5. What are differences between Diffusion, Osmosis and Active transport, facilitated

diffusion?

Diffusion: Passive movement of particles from high to low concentration.

Osmosis: Diffusion of water across a membrane.

Active Transport: Requires energy to move substances against the gradient.

Facilitate diffusion: ?????

Chapter 4:

1. Explain how ATP becomes ADP and vice-versa: Use a drawing if needed and label which molecule gives off energy in a cell.

ATP ↔ ADP:

• ATP releases energy by losing a phosphate group, becoming ADP.

• ADP gains a phosphate to store energy, becoming ATP.

2. Write the overall formula for Photosynthesis:

6CO2​+6H2​O+light energy→C6​H12​O6​+6O2​

3. Where does photosynthesis occur in the cell?

Chloroplast 

4. Fill in the table: Reactants, Products 

5. What is the overall reaction for Cellular respiration?

C6​H12​O6​+6O2​→6CO2​+6H2​O+energy (ATP)

6. Where does it occur in the cell?

Mitochondria 

7. Fill in the table:

Reactants  Products 

8. What is the reaction of Glycolysis?

Glycolysis is the breakdown of one molecule of glucose (C6H12O6) into two molecules of pyruvate (C3H4O3), producing a net gain of 2 ATP and 2 NADH.

9. What happens after Glycolysis if no oxygen is present?

If no oxygen is present, cells undergo anaerobic respiration or fermentation. Pyruvate is converted into either lactic acid (in animals) or ethanol and carbon dioxide (in plants, yeast, and some microorganisms) to regenerate NAD+ for glycolysis to continue.

10. What is fermentation called in plant and animal cells? Also list the products of each process:

• In plants/yeast: Alcoholic fermentation — Products: ethanol, carbon dioxide, and NAD+

• In animals: Lactic acid fermentation — Products: lactic acid and NAD+

Chapter 5:

1. Describe what happens in the following processes during the cell cycle:

- G 1: Cell grows and performs normal functions.

-Synthesis (S): DNA is replicated, resulting in two identical sister chromatids for each chromosome.

-G2: The cell continues to grow, produces proteins, and prepares for mitosis.

-Mitosis (M) and Cytokinesis: Mitosis divides the nucleus into two identical nuclei, and cytokinesis divides the cytoplasm, resulting in two identical daughter cells.

2. Why do cells need to have a high surface area to volume ratio?

A high surface area-to-volume ratio allows cells to efficiently exchange materials (like oxygen, nutrients, and waste) with their environment.

3. Draw and label a chromosome and explain how cells pack 3 meters of DNA into such a small space:

A chromosome consists of tightly coiled DNA around histone proteins, forming nucleosomes. These nucleosomes are further coiled and supercoiled to fit the DNA into a small, compact structure within the nucleus.

4. Draw and label what is happening in the cell as it goes through the following phases:

-Prophase: Chromosomes condense, nuclear envelope breaks down, and spindle fibers begin to form.

- Metaphase: Chromosomes align in the middle (equator) of the cell, attached to spindle fibers.

-Anaphase:Sister chromatids are pulled apart to opposite ends of the cell.

-Telophase: Nuclear membranes reform around each set of chromosomes, and the cell begins to divide.

5. Define:

-Growth factors: Proteins that stimulate cell division and growth.

-Apoptosis: Programmed cell death, which removes damaged or unnecessary cells.

6. Understand what cancer cells are and how they form.

Cancer cells are cells that divide uncontrollably due to mutations in genes that regulate the cell cycle, such as oncogenes and tumor suppressor genes. These mutations lead to unregulated cell growth and the formation of tumors.

7. Briefly describe Binary fission. What organisms reproduce using this method?

Binary fission is a form of asexual reproduction used by prokaryotic organisms (like bacteria). The DNA replicates, and the cell splits into two identical daughter cells.

8. Explain what stem cells are and why is there such a huge debate about using embryonic stem cells?

Stem cells are undifferentiated cells that can develop into specialized cell types. The debate about embryonic stem cells arises from ethical concerns, as harvesting them typically involves destroying an embryo.

Chapter 6:

1. How are Gametes and somatic cells different? (answer in terms of Diploid and Haploid

chromosome number)

Gametes: Haploid (n) cells, containing half the chromosome number (like sperm and egg).

Somatic cells: Diploid (2n) cells, containing the full set of chromosomes found in body cells.

2. Define:

- Homologous chromosomes: Pairs of chromosomes (one from each parent) with the same genes at the same loci, but possibly different alleles.

-Autosomes: Chromosomes that do not determine sex (humans have 22 pairs of autosomes).

-Sex Chromosomes: Chromosomes that determine sex (X and Y in humans).

3. How is meiosis different from mitosis (answer in terms of homologous chromosome pairs and sister chromatids separating). Also what are the products of each process?

• Meiosis: Homologous chromosomes separate in meiosis I, and sister chromatids separate in meiosis II. This results in four haploid cells (gametes).

• Mitosis: Sister chromatids separate, resulting in two identical diploid cells.

4. Who was Gregor Mendel and how did he come up with the law of segregation?

Gregor Mendel was a scientist who discovered the fundamental laws of inheritance through experiments on pea plants. The law of segregation states that during gamete formation, alleles for each gene separate, so each gamete carries only one allele for each trait.

5. Fill in the table:

6. Use a Punnett Square to perform a monohybrid cross on two plants one with red flowers and the other with White. The white is homozygous recessive and the Genotype of the red the flower is heterozygous. What are the genotypic and phenotypic ratios of the offspring?

Genotypic ratio: 1 Rr : 1 rr

Phenotypic ratio: 1 red : 1 white

7. Understand and be able to perform a test cross?

A test cross determines the genotype of an organism with a dominant phenotype by crossing it with a homozygous recessive organism.

8. Perform a Dihybrid Cross between an individual who has red flowers and long stems (RrLl)

and an individual with white flowers and Short stems (rrll). Explain the phenotype ratios.

Chapter 7:

1. Explain each of the following terms:

-Sex linked genes: Genes located on sex chromosomes (X or Y).

- X-Chromosome inactivation:  In female mammals, one of the X chromosomes is randomly inactivated in each cell.

- Incomplete dominance: A heterozygote shows an intermediate phenotype (like red and white flowers producing pink flowers).

- Codominance: Both alleles are fully expressed (like blood type AB).

2. What is a pedigree chart and why is it used? Be able to analyze a chart.

A pedigree chart tracks inheritance patterns of traits across generations, often used to study genetic disorders.

Chapter 8:

1. Draw and label the basic structure of a nucleotide:

A nucleotide consists of a phosphate group, a sugar (deoxyribose), and a nitrogenous base (A, T, C, or G)

2. List the 4 kinds of Nitrogenous bases and state which ones pair together:

Adenine (A) pairs with Thymine (T)

Cytosine (C) pairs with Guanine (G)

3. Use a labeled drawing to explain the process of replication. Be sure to include DNA polymerase in your explanation.

DNA replication is the process where DNA makes an identical copy of itself. Enzymes like helicase unwind the double helix, and DNA polymerase adds complementary nucleotides to form two identical strands.

4. Compare RNA transcription to DNA replication:

5. What 3 types of RNA are made and what is their function in the cell?

• mRNA: Carries genetic information from DNA to ribosomes.

• tRNA: Transfers amino acids to ribosomes.

• rRNA: Forms ribosomes, the site of protein synthesis.

6. What is a codon?

A codon is a sequence of 3 mRNA nucleotides that codes for a specific amino acid.

7. What is the start codon and how do start and stop codons control translation?

Start and stop codons control translation by signaling when to start and stop the process.

8. Describe the process of translation using a drawing. Be sure to include tRNA, amino acids, ribosome, and anticodons in the explanation

tRNA brings amino acids to the ribosome, matching anticodons to mRNA codons, forming a polypeptide.