Untitled Flashcards Set

Biologically Important Building Blocks

1. Fill in the blank: Amino acids consist of a ______, ______ group, and a variable ______ group.
   
   

   • Answer: Carbonyl, amino, R

2. Definition: What type of bond links amino acids together?
   
   

   • Answer: Peptide bond

3. Fill in the blank: The acidic amino acids are ______ and ______.
   
   

   • Answer: Glutamate (Glu), Aspartate (Asp)

4. Fill in the blank: The basic amino acids are ______, ______, and ______.
   
   

   • Answer: Histidine (His), Arginine (Arg), Lysine (Lys)

5. Definition: What type of bond is formed between two cysteine amino acids?
   
   

   • Answer: Disulfide bond

6. Fill in the blank: A cysteine that forms a disulfide bond is now called a ______.
   
   

   • Answer: Cystine

7. Definition: What is the primary structure of a protein?
   
   

   • Answer: Linear sequence of amino acids

8. Fill in the blank: The two main types of secondary protein structures are ______ and ______.
   
   

   • Answer: Alpha-helices, Beta-sheets

9. Fill in the blank: A beta-sheet can be arranged in ______ or ______ formation.
   
   

   • Answer: Parallel, Anti-parallel

10. Definition: What interactions are involved in tertiary protein structure?
    
    

    • Answer: Van der Waals forces, Disulfide bonds, Hydrophobic interactions, Hydrogen bonds

11. Fill in the blank: The interactions between different protein subunits make up ______ structure.
    
    

    • Answer: Quaternary

12. Definition: What are the five forces involved in quaternary structure?
    
    

    • Answer: Non-covalent interactions, Van der Waals forces, Hydrogen bonds, Electrostatic interactions, Disulfide bonds

Carbohydrates

13. Definition: What are the simplest forms of carbohydrates called?
    
    

    • Answer: Monosaccharides

14. Fill in the blank: Two monosaccharides linked together form a ______ via a ______ bond.
    
    

    • Answer: Disaccharide, Glycosidic

15. Definition: What are carbohydrates composed of more than two monosaccharides called?
    
    

    • Answer: Oligosaccharides (few), Polysaccharides (many)

16. Fill in the blank: ______ uses an alpha-glycosidic linkage, while ______ uses a beta-glycosidic linkage.
    
    

    • Answer: Glycogen, Cellulose

Lipids

17. Fill in the blank: The three major functions of lipids are ______, ______, and ______.

• Answer: Energy storage, Cell membrane barrier, Precursor to steroid hormones

18. Definition: What are the components of a fatty acid?

• Answer: Carboxyl group, Long hydrocarbon chain

19. Fill in the blank: Saturated fatty acids contain ______ double bonds, while unsaturated fatty acids contain ______ double bonds.

• Answer: No, One or more

20. Definition: What are the components of a triglyceride?

• Answer: Glycerol backbone, Three fatty acids

21. Fill in the blank: Phospholipids are composed of ______, ______, and ______.

• Answer: Glycerol, Two fatty acids, Phosphate group

22. Definition: What is the function of phospholipids in a membrane?

• Answer: Form bilayers that serve as the structural basis of cell membranes

23. Fill in the blank: ______ are the building blocks of steroids.

• Answer: Cholesterol

24. Definition: What are terpenes composed of?

• Answer: Isoprene units

25. Fill in the blank: A monoterpene consists of ______ isoprene units, a sesquiterpene has ______, and a diterpene has ______.

• Answer: Two, Three, Four

26. Definition: __________ are modified terpenes with additional functional groups

• Answer: Terpenoids

      27. Fill in the blank: Steroids have a ______ ring structure based on ______.

• Answer: Tetracyclic, Cholesterol

Phosphorus-Containing Compounds

28. Fill in the blank: Phosphate is also known as ______.

• Answer: Orthophosphate

29. Definition: What do two orthophosphates form when linked together?

• Answer: Pyrophosphate

30. Fill in the blank: The bonds linking phosphates are called ______ and store ______ energy.

• Answer: Anhydride linkages, High

Nucleotides

31. Definition: What are the three components of a nucleotide?

• Answer: Ribose/deoxyribose sugar, Nitrogenous base, 1-3 phosphate groups

32. Fill in the blank: The nitrogenous bases are divided into ______ (double rings) and ______ (single rings).

• Answer: Purines, Pyrimidines

33. Definition: Which bases are purines?

• Answer: Adenine (A), Guanine (G)

34. Definition: Which bases are pyrimidines?

• Answer: Cytosine (C), Thymine (T), Uracil (U)

35. Fill in the blank: DNA strands are linked by ______ bonds and run in ______ directions.

• Answer: Hydrogen, Antiparallel

36. Definition: What is the basic unit of chromatin?

• Answer: Nucleosome

Molecular Biology: DNA Structure

37. Definition: What are the building blocks of DNA?

• Answer: Nucleotides

38. Fill in the blank: DNA consists of a sugar-phosphate backbone and complementary base pairs held together by ______ bonds.

• Answer: Hydrogen

39. Definition: What is the difference between a purine and a pyrimidine?

• Answer: Purines have two rings (Adenine, Guanine), while pyrimidines have one ring (Cytosine, Thymine, Uracil)

40. Fill in the blank: DNA strands are always synthesized in the ______ direction.

• Answer: 5’ to 3’

41. Definition: What type of helix does DNA form according to the Watson-Crick model?

• Answer: Right-handed double helix

42. Fill in the blank: In eukaryotes, DNA is stored in ______ chromosomes, while in prokaryotes, DNA is found in ______ chromosomes.

• Answer: Linear, Circular

Genome Structure and Variation

43. Definition: What enzyme in prokaryotes supercoils DNA to fit inside the cell?

• Answer: DNA gyrase

44. Fill in the blank: Eukaryotic DNA is wrapped around proteins called ______, forming ______.

• Answer: Histones, Nucleosomes

45. Definition: What is the difference between heterochromatin and euchromatin?

• Answer: Heterochromatin is densely packed and transcriptionally inactive, while euchromatin is loosely packed and active

46. Fill in the blank: The region of a chromosome where spindle fibers attach during cell division is called the ______.

• Answer: Centromere

47. Definition: What are telomeres, and what is their function?

• Answer: Repetitive DNA sequences at chromosome ends that prevent loss of genetic material during replication

48. Fill in the blank: A ______ is a single base pair difference in the genome, while a ______ is a variation in the number of copies of a segment of DNA.

• Answer: SNP (Single Nucleotide Polymorphism), CNV (Copy Number Variation)

49. Definition: What are tandem repeats?

• Answer: Short sequences of nucleotides repeated one after another, often found in centromeres and telomeres

Role of DNA

50. Fill in the blank: The central dogma of molecular biology states that ______ is transcribed into ______, which is then translated into ______.

• Answer: DNA, RNA, Protein

51. Definition: What are the three stop codons, also known as nonsense codons?

• Answer: UAA, UAG, UGA

52. Fill in the blank: The genetic code is ______, meaning multiple codons can code for the same amino acid.

• Answer: Degenerate

DNA Replication

53. Fill in the blank: DNA replication occurs during the ______ phase of the cell cycle.

• Answer: S (Synthesis) phase

54. Definition: What enzyme unwinds the DNA double helix during replication?

• Answer: Helicase

55. Definition: What is the function of single-strand binding proteins (SSBPs)?

• Answer: They prevent DNA strands from re-annealing during replication.

56. Fill in the blank: The enzyme ______ synthesizes new DNA strands by adding nucleotides in the ______ direction.

• Answer: DNA Polymerase, 5’ to 3’

57. Definition: What is the role of primase in DNA replication?

• Answer: It synthesizes short RNA primers to provide a starting point for DNA polymerase.

58. Fill in the blank: The leading strand is synthesized ______, while the lagging strand is synthesized in short fragments called ______.

• Answer: Continuously, Okazaki fragments

59. Definition: What enzyme connects Okazaki fragments on the lagging strand?

• Answer: DNA Ligase

60. Fill in the blank: The enzyme ______ prevents excessive supercoiling by cutting and rejoining the DNA strands.

• Answer: Topoisomerase

61. Definition: What is the function of telomerase?

• Answer: It extends the telomeres at the ends of chromosomes to prevent loss of genetic material.

62. Fill in the blank: DNA replication is ______, meaning each new DNA molecule consists of one old strand and one new strand.

• Answer: Semiconservative

Genetic Mutation

63. Definition: What are mutagens?

• Answer: Agents that cause mutations in DNA.

64. Fill in the blank: Ionizing radiation can cause DNA damage by breaking ______.

• Answer: Both single and double strands of DNA

65. Definition: What type of mutation occurs when a single base pair is substituted?

• Answer: Point mutation

66. Fill in the blank: A ______ mutation results in a codon that codes for a different amino acid.

• Answer: Missense

67. Definition: What is a nonsense mutation?

• Answer: A mutation that creates a premature stop codon.

68. Fill in the blank: A ______ mutation does not change the amino acid sequence.

• Answer: Silent

69. Definition: What type of mutation results from the addition or deletion of nucleotides, shifting the reading frame?

• Answer: Frameshift mutation

70. Fill in the blank: ______ mutations occur naturally, while ______ mutations are caused by external factors.

• Answer: Spontaneous, Induced

71. Definition: What are transposons?

• Answer: Mobile genetic elements that can move within the genome and cause mutations.

72. Fill in the blank: A pair of transposons in the same direction can cause a ______, while transposons facing each other can cause an ______.

• Answer: Deletion, Inversion

DNA Repair

73. Definition: What is direct reversal in DNA repair?

• Answer: A process where damage is directly undone without cutting the DNA, such as UV damage repair.

74. Fill in the blank: Homology-dependent repair relies on the fact that DNA is ______ stranded.

• Answer: Double

75. Definition: What is the function of excision repair?

• Answer: It removes and replaces defective bases before DNA replication.

76. Fill in the blank: Mismatch repair corrects errors in DNA ______ replication.

• Answer: After

77. Definition: What is homologous recombination in double-strand break repair?

• Answer: A process that uses a sister chromatid as a template to accurately repair broken DNA.

78. Fill in the blank: Nonhomologous end joining directly connects broken DNA ends but is ______ prone.

• Answer: Error

Gene Expression: Transcription

79. Definition: What enzyme synthesizes RNA from a DNA template?

• Answer: RNA Polymerase

80. Fill in the blank: In prokaryotes, RNA polymerase binds to the ______ box at the promoter region.

• Answer: Pribnow

81. Definition: What are the three major types of RNA?

• Answer: mRNA (messenger), rRNA (ribosomal), tRNA (transfer)

82. Fill in the blank: In eukaryotes, the process of removing introns from pre-mRNA is called ______.

• Answer: Splicing

83. Definition: What is the role of the 5’ cap and poly-A tail in eukaryotic mRNA?

• Answer: They protect mRNA from degradation and help with translation.

Gene Expression: Translation

84. Definition: What are the three steps of translation?

• Answer: Initiation, Elongation, Termination

85. Fill in the blank: Translation occurs in the ______ of both prokaryotic and eukaryotic cells.

• Answer: Cytoplasm

86. Definition: What is the role of tRNA in translation?

• Answer: It carries amino acids to the ribosome and matches them with the correct mRNA codons.

87. Fill in the blank: The ribosome has three sites: ______, ______, and ______.

• Answer: A (Aminoacyl), P (Peptidyl), E (Exit)

88. Definition: What is wobble pairing?

• Answer: The ability of the third base in a tRNA anticodon to pair flexibly with different codons.

89. Fill in the blank: In prokaryotes, translation starts at the ______ sequence, while in eukaryotes it starts at the ______ sequence.

• Answer: Shine-Dalgarno, Kozak

90. Definition: What is the function of peptidyl transferase in translation?

• Answer: It forms peptide bonds between amino acids.

91. Fill in the blank: Termination of translation occurs when a ______ codon enters the ribosome.

• Answer: Stop

92. Definition: What energy molecule is required for translation?

• Answer: GTP

Controlling Gene Expression

93. Fill in the blank: Gene expression can be controlled at the ______, ______, or ______ levels.

• Answer: DNA, RNA, Protein

94. Definition: How does DNA methylation affect gene expression?

• Answer: It silences genes by blocking transcription factors.

95. Fill in the blank: In female mammals, one X chromosome is randomly inactivated, forming a ______ body.

• Answer: Barr

96. Definition: What is an operon?

• Answer: A cluster of genes controlled by a single promoter in prokaryotes.

97. Fill in the blank: The lac operon is an ______ system that is activated when ______ is present.

• Answer: Inducible, Lactose

98. Definition: What is the trp operon?

• Answer: A repressible operon that is turned off when tryptophan is present.

99. Fill in the blank: Eukaryotic transcription factors regulate gene expression by binding to ______ regions.

• Answer: Promoter or enhancer

100. Definition: What is RNA interference (RNAi)?

• Answer: A process where small RNA molecules degrade or block mRNA translation.

Viruses

101. Definition: What are viruses?

• Answer: Obligate intracellular parasites that require a host cell to replicate.

102. Fill in the blank: Viruses lack ______ and cannot carry out metabolism independently.

• Answer: Ribosomes

103. Definition: What is the protein shell of a virus called?

• Answer: Capsid

104. Fill in the blank: A virus with a lipid membrane derived from the host is called an ______ virus.

• Answer: Enveloped

105. Definition: What are the two major viral life cycles?

• Answer: Lytic cycle, Lysogenic cycle

106. Fill in the blank: In the ______ cycle, viruses replicate rapidly and lyse the host cell.

• Answer: Lytic

107. Definition: What is a provirus/prophage?

• Answer: A viral genome integrated into the host's DNA in the lysogenic cycle.

108. Fill in the blank: Retroviruses use the enzyme ______ to convert their RNA genome into DNA.

• Answer: Reverse transcriptase

109. Definition: What is a positive-sense RNA virus?

• Answer: A virus that carries RNA that can be directly translated into protein.

110. Fill in the blank: A negative-sense RNA virus requires the enzyme ______ to synthesize a complementary strand.

• Answer: RNA-dependent RNA polymerase

Subviral Particles

111. Definition: What are prions?

• Answer: Infectious proteins that cause misfolding of normal proteins.

112. Fill in the blank: Prions cause diseases by inducing abnormal ______ in proteins.

• Answer: Folding

113. Definition: What are viroids?

• Answer: Short pieces of circular RNA that can silence genes in host cells.

Prokaryotes (Bacteria)

114. Definition: What are the three domains of life?

• Answer: Bacteria, Archaea, Eukarya

115. Fill in the blank: Bacteria lack ______ and have a single circular chromosome.

• Answer: Membrane-bound organelles

116. Definition: What are plasmids?

• Answer: Small circular DNA molecules in bacteria that carry extra genes.

117. Fill in the blank: The bacterial cell wall is made of ______.

• Answer: Peptidoglycan

118. Definition: What is the difference between Gram-positive and Gram-negative bacteria?

• Answer: Gram-positive bacteria have a thick peptidoglycan layer, while Gram-negative bacteria have a thin layer and an outer membrane.

119. Fill in the blank: The space between the cell membrane and outer membrane in Gram-negative bacteria is called the ______.

• Answer: Periplasmic space

120. Definition: What are the three bacterial shapes?

• Answer: Cocci (spherical), Bacilli (rod-shaped), Spirilla (spiral)

121. Fill in the blank: Bacteria with flagella are considered ______.

• Answer: Motile

122. Definition: What is chemotaxis?

• Answer: Movement of bacteria toward or away from chemical stimuli.

123. Fill in the blank: The bacterial ______ helps bacteria adhere to surfaces and evade immune defenses.

• Answer: Capsule (glycocalyx)

Bacterial Growth & Reproduction

124. Definition: How do bacteria reproduce?

• Answer: Binary fission

125. Fill in the blank: The time required for a bacterial population to double is called the ______ time.

• Answer: Doubling

126. Definition: What are the four phases of bacterial growth?

• Answer: Lag phase, Log phase, Stationary phase, Death phase

127. Fill in the blank: During the ______ phase, bacteria prepare for rapid division but do not yet divide.

• Answer: Lag

128. Definition: What happens during the log phase?

• Answer: Bacteria multiply exponentially.

129. Fill in the blank: The ______ phase occurs when resources become limited and growth slows.

• Answer: Stationary

130. Definition: What happens during the death phase?

• Answer: Bacteria die as resources are depleted.

131. Fill in the blank: Bacteria that can survive harsh conditions by forming ______ are called spore-forming bacteria.

• Answer: Endospores

Bacterial Genetic Exchange

132. Definition: What are the three methods of genetic exchange in bacteria?

• Answer: Transformation, Transduction, Conjugation

133. Fill in the blank: In ______, bacteria take up naked DNA from the environment.

• Answer: Transformation

134. Definition: What is transduction?

• Answer: Transfer of bacterial genes via a bacteriophage (virus).

135. Fill in the blank: In conjugation, a ______ connects two bacteria, allowing DNA transfer.

• Answer: Sex pilus

136. Definition: What is the F factor?

• Answer: A plasmid that allows bacteria to form a sex pilus and transfer genetic material.

137. Fill in the blank: Bacteria that contain the F factor are designated as ______, while those without it are ______.

• Answer: F+, F-

138. Definition: What are Hfr bacteria?

• Answer: Bacteria with the F factor integrated into their chromosome.

The Organelles

139. Definition: What is the function of the nucleus?

• Answer: Stores genetic material (DNA) and controls cell activities.

140. Fill in the blank: The nuclear envelope has ______ layers and contains ______ to regulate material exchange.

• Answer: Two, Nuclear pores

141. Definition: What is the nucleolus?

• Answer: A dense region in the nucleus where ribosomes are assembled.

142. Fill in the blank: The ______ is the site of ATP production and has its own DNA.

• Answer: Mitochondrion

143. Definition: What is the endosymbiotic theory?

• Answer: The theory that mitochondria originated from an ancient symbiotic relationship between bacteria and early eukaryotic cells.

144. Fill in the blank: The rough ER is studded with ______ and is involved in ______ synthesis.

• Answer: Ribosomes, Protein

145. Definition: What is the function of the smooth ER?

• Answer: Lipid synthesis and detoxification.

146. Fill in the blank: The ______ modifies, sorts, and packages proteins for secretion.

• Answer: Golgi apparatus

147. Definition: What is the function of lysosomes?

• Answer: Break down cellular waste and foreign substances using digestive enzymes.

148. Fill in the blank: Peroxisomes break down ______ using the enzyme ______.

• Answer: Hydrogen peroxide, Catalase

The Plasma Membrane

149. Definition: What is the plasma membrane composed of?

• Answer: Phospholipid bilayer, proteins, cholesterol, and carbohydrates.

150. Fill in the blank: The fluid mosaic model describes the plasma membrane as a ______ structure with proteins embedded in a ______ layer.

• Answer: Dynamic, Phospholipid

151. Definition: What is the role of cholesterol in the plasma membrane?

• Answer: Regulates membrane fluidity.

152. Fill in the blank: Membrane proteins can be classified as ______ or ______.

• Answer: Integral, Peripheral

153. Definition: What are the three types of passive transport?

• Answer: Simple diffusion, Facilitated diffusion, Osmosis

154. Fill in the blank: Active transport requires ______ to move molecules ______ their concentration gradient.

• Answer: ATP, Against

155. Definition: What are the three types of active transport?

• Answer: Primary active transport, Secondary active transport, Bulk transport

156. Fill in the blank: The sodium-potassium pump moves ______ Na⁺ ions out of the cell and ______ K⁺ ions into the cell.

• Answer: 3, 2

157. Definition: What is endocytosis?

• Answer: The process of engulfing material into the cell via vesicles.

158. Fill in the blank: ______ is the process of cellular drinking, while ______ is the process of cellular eating.

• Answer: Pinocytosis, Phagocytosis

159. Definition: What is exocytosis?

• Answer: The release of substances from the cell via vesicles.

Transmembrane Transport

160. Definition: What is simple diffusion?

• Answer: Movement of molecules down their concentration gradient without the use of a membrane protein.

161. Fill in the blank: Facilitated diffusion requires ______ to transport molecules across the membrane.

• Answer: Carrier or channel proteins

162. Definition: What is osmosis?

• Answer: The movement of water across a membrane from a region of low solute concentration to high solute concentration.

163. Fill in the blank: The osmotic pressure equation is Π = ______.

• Answer: MiRT (where M = molarity, i = Van’t Hoff factor, R = gas constant, T = temperature in Kelvin)

164. Definition: What are the three types of tonicity?

• Answer: Hypertonic (water moves out of the cell), Hypotonic (water moves into the cell), Isotonic (no net movement).

165. Fill in the blank: Primary active transport uses ______ directly, while secondary active transport uses an existing ______ to move substances.

• Answer: ATP, Ion gradient

166. Definition: What is the function of an antiporter?

• Answer: Transports two different molecules in opposite directions across the membrane.

167. Fill in the blank: The Na+/K+ ATPase pump maintains a ______ charge inside the cell compared to the outside.

• Answer: Negative

Cell Cycle & Mitosis

168. Definition: What are the four phases of the cell cycle?

• Answer: G1 (growth), S (DNA replication), G2 (preparation for mitosis), M (mitosis).

169. Fill in the blank: Non-dividing cells enter a resting phase called ______.

• Answer: G0

170. Definition: What are the stages of mitosis?

• Answer: Prophase, Metaphase, Anaphase, Telophase

171. Fill in the blank: During ______, chromatin condenses into chromosomes and the nuclear envelope breaks down.

• Answer: Prophase

172. Definition: What happens in metaphase?

• Answer: Chromosomes align at the metaphase plate.

173. Fill in the blank: During anaphase, ______ pull sister chromatids to opposite poles of the cell.

• Answer: Spindle fibers

174. Definition: What happens during telophase?

• Answer: Nuclear envelopes reform around the separated chromosomes.

175. Fill in the blank: The process that divides the cytoplasm and results in two daughter cells is called ______.

• Answer: Cytokinesis

Control of the Cell Cycle

176. Definition: What are cyclins and cyclin-dependent kinases (CDKs)?

• Answer: Regulatory proteins that control progression through the cell cycle.

177. Fill in the blank: The ______ checkpoint ensures DNA is undamaged before replication.

• Answer: G1/S

178. Definition: What is the function of the G2/M checkpoint?

• Answer: Ensures DNA replication was successful before entering mitosis.

179. Fill in the blank: The ______ protein is a tumor suppressor that prevents cell cycle progression in response to DNA damage.

• Answer: p53

180. Definition: What is apoptosis?

• Answer: Programmed cell death that eliminates damaged or unnecessary cells.

181. Fill in the blank: Cancer occurs when cells lose control over the ______.

• Answer: Cell cycle

182. Definition: What is the difference between oncogenes and tumor suppressor genes?

• Answer: Oncogenes promote uncontrolled cell growth, while tumor suppressor genes prevent it.

Cancer, Oncogenes, and Tumor Suppressors

183. Definition: What is cancer?

• Answer: Uncontrolled cell division due to genetic mutations.

184. Fill in the blank: A gene that promotes cell division and can lead to cancer when mutated is called an ______.

• Answer: Oncogene

185. Definition: What are proto-oncogenes?

• Answer: Normal genes that regulate cell growth but can become oncogenes if mutated.

186. Fill in the blank: The ______ gene is a tumor suppressor that helps prevent cancer by repairing DNA or inducing apoptosis.

• Answer: p53

187. Definition: What is metastasis?

• Answer: The spread of cancer cells to distant parts of the body.

188. Fill in the blank: Cancer cells often have mutations in ______ that control the cell cycle.

• Answer: Checkpoint proteins

Tissue Formation

189. Definition: What are the four major types of tissue in the human body?

• Answer: Epithelial, Connective, Muscle, Nervous

190. Fill in the blank: ______ tissue covers body surfaces and lines internal organs.

• Answer: Epithelial

191. Definition: What is connective tissue?

• Answer: Tissue that provides support and connects different parts of the body (e.g., bone, blood, cartilage).

192. Fill in the blank: Muscle tissue is responsible for ______.

• Answer: Movement

193. Definition: What is the function of nervous tissue?

• Answer: Transmitting electrical signals throughout the body.

Genetics and Evolution

194. Definition: What is genetics?

• Answer: The study of heredity and variation in organisms.

195. Fill in the blank: An organism’s genetic makeup is called its ______, while its physical characteristics are its ______.

• Answer: Genotype, Phenotype

196. Definition: What is the law of segregation?

• Answer: Each individual has two alleles for each gene, and these alleles separate during gamete formation.

197. Fill in the blank: The law of independent assortment states that genes for different traits segregate ______ during meiosis.

• Answer: Independently

198. Definition: What is a dominant allele?

• Answer: An allele that is expressed if present.

199. Fill in the blank: A recessive allele is only expressed when an individual has ______ copies.

• Answer: Two

200. Definition: What is incomplete dominance?

• Answer: A situation where the heterozygote has an intermediate phenotype between the dominant and recessive traits.

201. Fill in the blank: In codominance, both alleles are ______ expressed in a heterozygous individual.

• Answer: Fully

202. Definition: What are linked genes?

• Answer: Genes that are located close together on the same chromosome and tend to be inherited together.

203. Fill in the blank: The closer two genes are on a chromosome, the ______ likely they are to be separated by recombination.

• Answer: Less

Meiosis

204. Definition: What is meiosis?

• Answer: A type of cell division that produces four haploid gametes from a diploid cell.

205. Fill in the blank: Meiosis consists of ______ and ______ divisions.

• Answer: Meiosis I, Meiosis II

206. Definition: What happens during prophase I of meiosis?

• Answer: Homologous chromosomes pair up and exchange genetic material through crossing over.

207. Fill in the blank: The structure formed by homologous chromosomes during prophase I is called a ______.

• Answer: Tetrad

208. Definition: What is the significance of crossing over in meiosis?

• Answer: It increases genetic diversity by exchanging DNA between homologous chromosomes.

209. Fill in the blank: Homologous chromosomes separate during ______, while sister chromatids separate during ______.

• Answer: Anaphase I, Anaphase II

210. Definition: What is the difference between mitosis and meiosis?

• Answer: Mitosis produces two identical diploid cells, while meiosis produces four genetically unique haploid cells.

Mendelian Genetics

211. Definition: What is a monohybrid cross?

• Answer: A genetic cross involving one trait with two alleles.

212. Fill in the blank: A heterozygous cross (Aa × Aa) results in a genotypic ratio of ______ and a phenotypic ratio of ______.

• Answer: 1:2:1, 3:1

213. Definition: What is a test cross?

• Answer: A cross between an individual with a dominant phenotype and a homozygous recessive individual to determine the unknown genotype.

214. Fill in the blank: A dihybrid cross (AaBb × AaBb) results in a phenotypic ratio of ______.

• Answer: 9:3:3:1

215. Definition: What is epistasis?

• Answer: A form of genetic interaction where one gene affects the expression of another gene.

Population Genetics

216. Definition: What is population genetics?

• Answer: The study of genetic variation within populations.

217. Fill in the blank: The Hardy-Weinberg equilibrium equation is ______.

• Answer: p² + 2pq + q² = 1

218. Definition: What are the five conditions required for Hardy-Weinberg equilibrium?

• Answer: Large population size, No mutation, No migration, Random mating, No natural selection.

219. Fill in the blank: If the frequency of a recessive allele (q) is 0.3, the frequency of the dominant allele (p) is ______.

• Answer: 0.7 (since p + q = 1)

220. Definition: What is genetic drift?

• Answer: Random changes in allele frequencies due to chance events, especially in small populations.

221. Fill in the blank: A sudden reduction in population size due to disaster, leading to reduced genetic diversity, is called the ______ effect.

• Answer: Bottleneck

222. Definition: What is the founder effect?

• Answer: When a small group establishes a new population, leading to reduced genetic variation.

Evolution by Natural Selection

223. Definition: What is evolution?

• Answer: Change in allele frequencies in a population over time.

224. Fill in the blank: Natural selection acts on an organism’s ______, not its ______.

• Answer: Phenotype, Genotype

225. Definition: What are the three types of natural selection?

• Answer: Directional selection, Stabilizing selection, Disruptive selection.

226. Fill in the blank: In ______ selection, individuals with extreme traits are favored over intermediate traits.

• Answer: Disruptive

227. Definition: What is sexual selection?

• Answer: A type of natural selection where traits increase an organism’s chance of mating.

228. Fill in the blank: When different species evolve similar traits due to similar environments, it is called ______ evolution.

• Answer: Convergent

229. Definition: What is adaptive radiation?

• Answer: The rapid evolution of multiple species from a common ancestor to occupy different ecological niches.

Speciation & Phylogeny

230. Definition: What is speciation?

• Answer: The formation of new species from existing species over time.

231. Fill in the blank: When a population becomes geographically isolated and evolves into a new species, it is called ______ speciation.

• Answer: Allopatric

232. Definition: What is sympatric speciation?

• Answer: The formation of new species within the same geographic area, often due to reproductive isolation.

233. Fill in the blank: The evolutionary relationships among species are depicted in a ______.

• Answer: Phylogenetic tree

234. Definition: What is the molecular clock hypothesis?

• Answer: The idea that genetic mutations accumulate at a relatively constant rate, allowing scientists to estimate evolutionary timelines.

The Nervous System

235. Definition: What are the two main divisions of the nervous system?

• Answer: Central Nervous System (CNS) and Peripheral Nervous System (PNS)

236. Fill in the blank: The CNS consists of the ______ and ______.

• Answer: Brain, Spinal cord

237. Definition: What are the two divisions of the peripheral nervous system?

• Answer: Somatic (voluntary) and Autonomic (involuntary) nervous systems

238. Fill in the blank: The autonomic nervous system is further divided into the ______ and ______ divisions.

• Answer: Sympathetic, Parasympathetic

239. Definition: What is the role of the sympathetic nervous system?

• Answer: Activates the "fight or flight" response, increasing heart rate and energy availability.

240. Fill in the blank: The parasympathetic nervous system promotes the "______ and ______" response.

• Answer: Rest, Digest

Neurons

241. Definition: What are neurons?

• Answer: Specialized cells that transmit electrical and chemical signals in the nervous system.

242. Fill in the blank: The three main parts of a neuron are the ______, ______, and ______.

• Answer: Dendrites, Soma (cell body), Axon

243. Definition: What is the function of dendrites?

• Answer: Receive incoming signals from other neurons.

244. Fill in the blank: The axon transmits signals ______ from the cell body.

• Answer: Away

245. Definition: What is the myelin sheath?

• Answer: A fatty layer that insulates axons and increases the speed of nerve impulse transmission.

246. Fill in the blank: Myelin in the CNS is produced by ______, while myelin in the PNS is produced by ______.

• Answer: Oligodendrocytes, Schwann cells

247. Definition: What are the gaps between myelinated sections of an axon called?

• Answer: Nodes of Ranvier

248. Fill in the blank: The rapid transmission of an action potential between nodes of Ranvier is called ______ conduction.

• Answer: Saltatory

249. Definition: What is the resting membrane potential of a neuron?

• Answer: Approximately -70 mV

250. Fill in the blank: The resting membrane potential is maintained by the ______ pump, which moves 3 ______ ions out and 2 ______ ions in.

• Answer: Sodium-potassium, Na+, K+

Action Potentials

251. Definition: What is an action potential?

• Answer: A rapid change in membrane potential that allows neurons to transmit electrical signals.

252. Fill in the blank: An action potential is triggered when the membrane potential reaches the ______.

• Answer: Threshold (-55 mV)

253. Definition: What ion channels open during depolarization?

• Answer: Voltage-gated Na+ channels

254. Fill in the blank: Depolarization causes the inside of the neuron to become more ______.

• Answer: Positive

255. Definition: What happens during repolarization?

• Answer: Voltage-gated K+ channels open, allowing K+ to exit the cell, restoring a negative membrane potential.

256. Fill in the blank: The brief period when a neuron cannot fire another action potential is called the ______.

• Answer: Refractory period

257. Definition: What is the difference between absolute and relative refractory periods?

• Answer: In the absolute refractory period, no action potential can be triggered; in the relative refractory period, a stronger stimulus is required.

Synaptic Transmission

258. Definition: What is a synapse?

• Answer: The junction between two neurons or between a neuron and an effector cell.

259. Fill in the blank: The two types of synapses are ______ and ______.

• Answer: Electrical, Chemical

260. Definition: What happens at a chemical synapse?

• Answer: Neurotransmitters are released from the presynaptic neuron and bind to receptors on the postsynaptic cell.

261. Fill in the blank: The influx of ______ ions into the axon terminal triggers neurotransmitter release.

• Answer: Calcium (Ca²⁺)

262. Definition: What is the role of neurotransmitters?

• Answer: They transmit signals across the synaptic cleft by binding to receptors on the postsynaptic cell.

263. Fill in the blank: An excitatory neurotransmitter causes ______, while an inhibitory neurotransmitter causes ______.

• Answer: Depolarization, Hyperpolarization

264. Definition: What is reuptake?

• Answer: The process of removing neurotransmitters from the synaptic cleft by reabsorbing them into the presynaptic neuron.

265. Fill in the blank: Acetylcholine is the primary neurotransmitter at ______ junctions.

• Answer: Neuromuscular

The Endocrine System

266. Definition: What is the endocrine system?

• Answer: A system of glands that secrete hormones into the bloodstream to regulate body functions.

267. Fill in the blank: Hormones travel through the ______ to reach their target cells.

• Answer: Bloodstream

268. Definition: What are the two main types of hormones?

• Answer: Peptide hormones and steroid hormones

269. Fill in the blank: Peptide hormones bind to ______ receptors, while steroid hormones bind to ______ receptors.

• Answer: Surface, Intracellular

270. Definition: What is the role of the hypothalamus in the endocrine system?

• Answer: It regulates the pituitary gland and connects the nervous system to the endocrine system.

271. Fill in the blank: The pituitary gland is divided into the ______ and ______ lobes.

• Answer: Anterior, Posterior

272. Definition: What hormones are secreted by the anterior pituitary?

• Answer: FSH, LH, ACTH, TSH, Prolactin, GH (FLAT PiG)

273. Fill in the blank: The posterior pituitary releases ______ and ______.

• Answer: Oxytocin, ADH (Vasopressin)

274. Definition: What is the function of antidiuretic hormone (ADH)?

• Answer: It increases water retention by the kidneys to regulate blood pressure.

275. Fill in the blank: The thyroid gland secretes ______ and ______ to regulate metabolism.

• Answer: T3 (triiodothyronine), T4 (thyroxine)

276. Definition: What is the role of calcitonin?

• Answer: Lowers blood calcium levels by promoting calcium deposition in bones.

277. Fill in the blank: The parathyroid gland releases ______ to increase blood calcium levels.

• Answer: Parathyroid hormone (PTH)

278. Definition: What are the two parts of the adrenal glands?

• Answer: Adrenal cortex and adrenal medulla

279. Fill in the blank: The adrenal medulla secretes ______ and ______ in response to stress.

• Answer: Epinephrine, Norepinephrine

280. Definition: What are the three types of steroid hormones produced by the adrenal cortex?

• Answer: Glucocorticoids (cortisol), Mineralocorticoids (aldosterone), Sex steroids

281. Fill in the blank: Insulin ______ blood glucose levels, while glucagon ______ blood glucose levels.

• Answer: Decreases, Increases

282. Definition: What is the function of the pancreas in the endocrine system?

• Answer: It regulates blood sugar levels through insulin and glucagon secretion.

283. Fill in the blank: The pineal gland produces ______, which regulates sleep-wake cycles.

• Answer: Melatonin

The Muscular System

284. Definition: What are the three types of muscle tissue?

• Answer: Skeletal muscle, Cardiac muscle, Smooth muscle

285. Fill in the blank: Skeletal muscle is under ______ control, while cardiac and smooth muscle are under ______ control.

• Answer: Voluntary, Involuntary

286. Definition: What is the basic contractile unit of a muscle fiber?

• Answer: Sarcomere

287. Fill in the blank: The thick filaments in a sarcomere are composed of ______, while the thin filaments are composed of ______.

• Answer: Myosin, Actin

288. Definition: What is the sliding filament model?

• Answer: The theory that muscle contraction occurs when myosin pulls actin filaments toward the center of the sarcomere.

289. Fill in the blank: Calcium binds to ______, allowing myosin to interact with actin.

• Answer: Troponin

290. Definition: What is the role of ATP in muscle contraction?

• Answer: It provides energy for myosin to detach from actin and reset for the next contraction.

291. Fill in the blank: A single motor neuron and all the muscle fibers it controls form a ______.

• Answer: Motor unit

292. Definition: What is the difference between fast-twitch and slow-twitch muscle fibers?

• Answer: Fast-twitch fibers contract quickly but fatigue easily; slow-twitch fibers contract slowly but are more resistant to fatigue.

The Skeletal System

293. Definition: What are the two main divisions of the skeletal system?

• Answer: Axial skeleton and Appendicular skeleton

294. Fill in the blank: The axial skeleton includes the ______, ______, and ______.

• Answer: Skull, Vertebral column, Rib cage

295. Definition: What are the two types of bone tissue?

• Answer: Compact bone and Spongy bone

296. Fill in the blank: The functional unit of compact bone is called the ______.

• Answer: Osteon (Haversian system)

297. Definition: What is the role of osteoblasts?

• Answer: Build bone by depositing minerals.

298. Fill in the blank: ______ break down bone tissue to release calcium into the bloodstream.

• Answer: Osteoclasts

299. Definition: What is the role of cartilage?

• Answer: Provides flexible support and reduces friction in joints.

300. Fill in the blank: Ligaments connect ______ to ______, while tendons connect ______ to ______.

• Answer: Bone to bone, Muscle to bone

The Cardiovascular System

301. Definition: What are the main components of the cardiovascular system?

• Answer: Heart, Blood vessels, Blood

302. Fill in the blank: The heart has ______ chambers: two ______ and two ______.

• Answer: Four, Atria, Ventricles

303. Definition: What are the three main types of blood vessels?

• Answer: Arteries, Veins, Capillaries

304. Fill in the blank: Arteries carry blood ______ from the heart, while veins carry blood ______ the heart.

• Answer: Away, Toward

305. Definition: What is the function of capillaries?

• Answer: Facilitate exchange of gases, nutrients, and waste between blood and tissues.

306. Fill in the blank: The left ventricle pumps blood into the ______ circulation, while the right ventricle pumps blood into the ______ circulation.

• Answer: Systemic, Pulmonary

307. Definition: What is systole?

• Answer: The phase of the cardiac cycle when the heart contracts to pump blood.

308. Fill in the blank: Diastole is the phase when the heart ______.

• Answer: Relaxes and fills with blood

309. Definition: What is blood pressure?

• Answer: The force exerted by blood on the walls of blood vessels.

310. Fill in the blank: The SA node, also called the ______, sets the heart’s rhythm.

• Answer: Pacemaker

311. Definition: What is the function of red blood cells?

• Answer: Transport oxygen using hemoglobin.

312. Fill in the blank: White blood cells function in the ______.

• Answer: Immune system

313. Definition: What is the role of platelets?

• Answer: Assist in blood clotting.

The Respiratory System

314. Definition: What is the primary function of the respiratory system?

• Answer: Gas exchange (oxygen intake and carbon dioxide removal).

315. Fill in the blank: The pathway of air begins at the ______, passes through the ______, and enters the lungs via the ______.

• Answer: Nose/Mouth, Trachea, Bronchi

316. Definition: What are alveoli?

• Answer: Tiny air sacs in the lungs where gas exchange occurs.

317. Fill in the blank: Oxygen diffuses from the ______ into the blood, while carbon dioxide diffuses from the ______ into the alveoli.

• Answer: Alveoli, Blood

318. Definition: What muscle controls breathing?

• Answer: Diaphragm

319. Fill in the blank: During inhalation, the diaphragm ______, increasing lung volume and decreasing pressure.

• Answer: Contracts

320. Definition: What is tidal volume?

• Answer: The amount of air inhaled or exhaled in a normal breath.

321. Fill in the blank: The total lung capacity is the sum of ______ volume and ______ volume.

• Answer: Tidal, Reserve

322. Definition: How is most oxygen transported in the blood?

• Answer: Bound to hemoglobin in red blood cells.

323. Fill in the blank: Carbon dioxide is transported as ______ in the blood.

• Answer: Bicarbonate (HCO₃⁻)

The Immune System

324. Definition: What are the two main divisions of the immune system?

• Answer: Innate (nonspecific) immunity and Adaptive (specific) immunity.

325. Fill in the blank: The first line of defense includes physical barriers such as ______ and ______.

• Answer: Skin, Mucous membranes

326. Definition: What is the function of macrophages?

• Answer: Engulf pathogens and present antigens to helper T cells.

327. Fill in the blank: The inflammatory response is triggered by the release of ______.

• Answer: Histamine

328. Definition: What are B cells responsible for?

• Answer: Producing antibodies in the humoral immune response.

329. Fill in the blank: Helper T cells activate ______ and ______ cells to mount an immune response.

• Answer: B cells, Cytotoxic T cells

330. Definition: What is the role of memory cells?

• Answer: Provide long-term immunity by remembering past infections.

331. Fill in the blank: Autoimmune diseases occur when the immune system attacks ______.

• Answer: The body’s own cells

The Digestive System

332. Definition: What are the main functions of the digestive system?

• Answer: Ingestion, digestion, absorption, elimination.

333. Fill in the blank: The digestive tract is also called the ______ canal.

• Answer: Alimentary

334. Definition: What is peristalsis?

• Answer: Involuntary muscle contractions that move food through the digestive tract.

335. Fill in the blank: Digestion begins in the ______, where food is broken down by ______.

• Answer: Mouth, Salivary enzymes

336. Definition: What is the role of the stomach in digestion?

• Answer: It secretes acid and enzymes to break down food into chyme.

337. Fill in the blank: The main site of nutrient absorption is the ______.

• Answer: Small intestine

338. Definition: What is the function of bile?

• Answer: Emulsifies fats to aid in digestion.

339. Fill in the blank: The pancreas secretes digestive enzymes into the ______.

• Answer: Small intestine

340. Definition: What is the role of the large intestine?

• Answer: Absorbs water and forms solid waste (feces).

341. Fill in the blank: The ______ is responsible for producing bile.

• Answer: Liver

342. Definition: What is the function of the gallbladder?

• Answer: Stores and releases bile into the small intestine.

The Excretory System

343. Definition: What is the primary function of the excretory system?

• Answer: Removal of waste products and regulation of water and electrolyte balance.

344. Fill in the blank: The main organs of the excretory system are the ______.

• Answer: Kidneys

345. Definition: What is the functional unit of the kidney?

• Answer: Nephron

346. Fill in the blank: The nephron consists of the ______, ______, and tubules.

• Answer: Glomerulus, Bowman’s capsule

347. Definition: What is the role of the glomerulus?

• Answer: Filters blood to form urine.

348. Fill in the blank: The loop of Henle helps concentrate urine by creating a ______ gradient.

• Answer: Salt

349. Definition: What is the function of antidiuretic hormone (ADH) in the kidneys?

• Answer: Increases water reabsorption in the collecting ducts.

350. Fill in the blank: The hormone ______ increases sodium reabsorption in the kidneys.

• Answer: Aldosterone

351. Definition: What are the three major nitrogenous wastes excreted by the kidneys?

• Answer: Urea, Uric acid, Creatinine

352. Fill in the blank: Urine exits the kidney through the ______, is stored in the ______, and is excreted through the ______.

• Answer: Ureter, Bladder, Urethra

The Reproductive System

353. Definition: What are the male gonads?

• Answer: Testes

354. Fill in the blank: The testes produce ______ and the hormone ______.

• Answer: Sperm, Testosterone

355. Definition: What is the function of the epididymis?

• Answer: Stores and matures sperm.

356. Fill in the blank: Sperm travel through the ______ to reach the urethra.

• Answer: Vas deferens

357. Definition: What are the female gonads?

• Answer: Ovaries

358. Fill in the blank: The ovaries produce ______ and the hormones ______ and ______.

• Answer: Eggs (ova), Estrogen, Progesterone

359. Definition: What is ovulation?

• Answer: The release of a mature egg from the ovary.

360. Fill in the blank: Fertilization typically occurs in the ______.

• Answer: Fallopian tube

361. Definition: What is the function of the placenta?

• Answer: Provides nutrients and oxygen to the developing fetus.

362. Fill in the blank: The hormone responsible for labor contractions is ______.

• Answer: Oxytocin

363. Definition: What is the menstrual cycle?

• Answer: A monthly cycle in females that regulates ovulation and preparation for pregnancy.

364. Fill in the blank: The menstrual cycle consists of the ______ phase, ______ phase, and ______ phase.

• Answer: Follicular, Ovulatory, Luteal

The Integumentary System

365. Definition: What are the main functions of the integumentary system?

• Answer: Protection, temperature regulation, sensation, excretion.

366. Fill in the blank: The skin consists of three main layers: the ______, ______, and ______.

• Answer: Epidermis, Dermis, Hypodermis

367. Definition: What is the outermost layer of the skin composed of?

• Answer: Keratinized epithelial cells

368. Fill in the blank: The pigment that gives skin its color is called ______.

• Answer: Melanin

369. Definition: What are sebaceous glands?

• Answer: Glands that secrete sebum (oil) to lubricate the skin and hair.

370. Fill in the blank: Sweat glands help regulate body temperature through ______.

• Answer: Evaporation

371. Definition: What is the role of hair in the integumentary system?

• Answer: Provides protection and helps regulate temperature.

372. Fill in the blank: Nails are composed of ______.

Answer: Keratin