B- forms and function

Question 1

What are the basic building blocks of life?

Answer 1

Molecules

Molecules form the foundation of cells, which in turn make up organisms.

Question 2

What is the smallest unit of life?

Answer 2

Cells

Cells are the basic structural and functional units of all living organisms.

Question 3

What is the term for a community of interacting organisms and their environment?

Answer 3

Ecosystem

Ecosystems consist of living organisms and their physical environment.

Question 4

What process involves the copying of DNA?

Answer 4

DNA replication

DNA replication is essential for cell division and the continuity of genetic information.

Question 5

What enzyme unwinds and unzips the DNA during replication?

Answer 5

DNA helicase

DNA helicase breaks hydrogen bonds to form the replication fork.

Question 6

What is the role of DNA polymerase III?

Answer 6

Synthesizes new DNA strands

DNA polymerase III adds nucleotides in a 5’ to 3’ direction.

Question 7

How does DNA polymerase I function in DNA replication?

Answer 7

Removes RNA primers and replaces them with DNA nucleotides

This enzyme ensures that the newly synthesized DNA is continuous.

Question 8

What is the purpose of the polymerase chain reaction (PCR)?

Answer 8

Amplifies small fragments of DNA

PCR is crucial for advancements in medical and forensic science.

Question 9

What are the stages of PCR?

Answer 9

Denaturation, Annealing, Extension

These stages involve heating DNA, binding primers, and replicating DNA.

Question 10

What is gel electrophoresis used for?

Answer 10

Separating DNA fragments based on size and charge

This technique allows visualization of DNA fragments after amplification.

Question 11

What is the primary product of transcription?

Answer 11

Messenger RNA (mRNA)

mRNA carries genetic information for protein synthesis.

Question 12

Where does transcription occur in eukaryotic cells?

Answer 12

Nucleus

In prokaryotic cells, transcription occurs in the cytoplasm.

Question 13

What is the role of transcription factors?

Answer 13

Bind to promoters to regulate transcription

They can increase or decrease RNA polymerase activity.

Question 14

What happens during the elongation phase of transcription?

Answer 14

RNA nucleotides find complementary bases on the DNA

RNA polymerase catalyzes the formation of covalent bonds between nucleotides.

Question 15

What is alternative splicing?

Answer 15

Allows one gene to code for multiple proteins

This process can remove additional exons from pre-mRNA.

Question 16

What is the function of tRNA?

Answer 16

Brings amino acids to the ribosome

tRNA has an anticodon that is complementary to mRNA codons.

Question 17

What is the start codon for translation?

Answer 17

AUG

This codon signals the beginning of protein synthesis.

Question 18

What is the role of ribosomes in translation?

Answer 18

Facilitate the synthesis of proteins

Ribosomes consist of large and small subunits that coordinate tRNA and mRNA.

Question 19

What are the three binding sites on a ribosome?

Answer 19

A, P, E sites

A site holds the tRNA carrying the next amino acid; P site holds the growing polypeptide; E site is where tRNA exits.

Question 20

What is a mutation?

Answer 20

Permanent structural changes to genes

Mutations can affect protein function and may be beneficial, neutral, or harmful.

Question 21

What are single-nucleotide polymorphisms (SNPs)?

Answer 21

Base substitutions in DNA sequence

SNPs can be synonymous (no change in amino acid) or non-synonymous (change in amino acid).

Question 22

What is the CRISPR-Cas9 system used for?

Answer 22

Gene editing

This system allows for precise modifications of DNA sequences.

Question 23

What is the function of cyclins in the cell cycle?

Answer 23

Regulate the progression of the cell cycle

Cyclins activate enzymes that phosphorylate target proteins.

Question 24

What is the outcome of mitosis?

Answer 24

Production of diploid daughter cells

Mitosis results in cells that are genetically identical to the parent cell.

Question 25

What is the process of oogenesis?

Answer 25

Production of mature eggs in humans ## Footnote Oogenesis involves unequal distribution of cytoplasmic content.

Question 26

What is the role of proto-oncogenes?

Answer 26

Promote cell growth ## Footnote When mutated, they can become oncogenes and contribute to cancer development.

Question 27

What is phenotypic plasticity?

Answer 27

Ability of genotype to produce different phenotypes ## Footnote This occurs when individuals are exposed to varying environmental conditions.

Question 28

What is non-disjunction?

Answer 28

Failure of chromosomes to separate properly during meiosis ## Footnote It can lead to conditions like trisomy or monosomy.

Question 29

What is gene expression regulation by enhancers?

Answer 29

Enhancers are non-coding DNA that can be found at various distances from the gene and regulate gene expression by promoting RNA polymerase binding to the promoter through activator proteins. ## Footnote Enhancers increase gene expression.

Question 30

How does mRNA degradation affect gene expression?

Answer 30

mRNA degradation controls the extent of gene expression, as mRNA can be translated multiple times before degradation occurs. ## Footnote Nucleases break down mRNA, affecting its persistence.

Question 31

What is the role of the poly-A tail in mRNA?

Answer 31

The poly-A tail at the 3’ end increases the structural stability of mRNA, allowing it to persist longer and be translated multiple times. ## Footnote This stability is influenced by the presence of stabilizing proteins.

Question 32

What is the function of stabilizing proteins in relation to mRNA?

Answer 32

Stabilizing proteins interfere with the activity of nucleases, blocking their active sites and preventing them from degrading mRNA. ## Footnote They promote binding to mRNA and can also facilitate degradation.

Question 33

What are epigenetic tags?

Answer 33

Epigenetic tags are chemical groups (methyl and acetyl) added to DNA and/or histones that alter transcription rates by promoting or inhibiting RNA polymerase binding. ## Footnote They can result in changes in gene expression across different cells and tissues.

Question 34

What is histone acetylation?

Answer 34

Histone acetylation is the addition of an acetyl group to a histone tail, decreasing the overall charge of histones and reducing the attraction between histones and DNA. ## Footnote This allows RNA polymerase to bind to the promoter and facilitates gene expression.

Question 35

What is DNA methylation?

Answer 35

DNA methylation involves the addition of a methyl group to cytosine in a promoter, which represses transcription by preventing transcription factors from binding. ## Footnote This results in decreased gene expression or gene silencing.

Question 36

What is epigenetic inheritance?

Answer 36

Epigenetic inheritance is the transmission of non-genetic information that can influence gene expression across generations. ## Footnote Changes must be maintained in egg and sperm cells to be passed on.

Question 37

What happens to epigenetic tags shortly after fertilization?

Answer 37

The majority of epigenetic tags are removed from DNA, resetting the epigenetic environment of the genome. ## Footnote This process eliminates modifications acquired during the parents' lifetimes.

Question 38

What is the lac operon?

Answer 38

The lac operon is a cluster of three genes in bacterial DNA that codes for proteins that digest lactose, allowing bacteria to utilize lactose as an energy source when glucose is absent. ## Footnote It is regulated by the presence or absence of lactose.

Question 39

What occurs during the acrosome reaction in fertilization?

Answer 39

The acrosome reaction involves the digestion of the zona pellucida to allow sperm to reach the plasma membrane of the egg. ## Footnote This is crucial for successful fertilization.

Question 40

What is the primary function of hCG during pregnancy?

Answer 40

hCG maintains the corpus luteum, allowing continual production of estrogen and progesterone after implantation. ## Footnote This is essential for maintaining the endometrium.

Question 41

What is the difference between spermatogenesis and oogenesis?

Answer 41

Spermatogenesis produces four haploid sperm cells, while oogenesis results in one ovum and polar bodies with limited cytoplasm. ## Footnote Both processes occur through meiosis but have different outcomes.

Question 42

What is the role of testosterone in male puberty?

Answer 42

Testosterone initiates the development of secondary sexual characteristics and regulates the negative feedback on GnRH, FSH, and LH secretion. ## Footnote This hormonal regulation begins at puberty.

Question 43

What is the significance of Mendel's experiments?

Answer 43

Mendel's experiments demonstrated the inheritance of traits through selective breeding, leading to the understanding of genetic inheritance patterns. ## Footnote His work laid the foundation for modern genetics.

Question 44

True or False: High blood glucose levels trigger the secretion of glucagon.

Answer 44

False ## Footnote High blood glucose levels trigger the secretion of insulin, while low levels trigger glucagon.

Question 45

What physiological mechanisms do birds and mammals use for thermoregulation?

Answer 45

Birds and mammals use both physiological and behavioral mechanisms to regulate body temperature, coordinated by the nervous system. ## Footnote This includes responses like shivering and sweating.

Question 46

Fill in the blank: The process of _______ involves the fusion of male and female gametes to form a diploid zygote.

Answer 46

fertilization ## Footnote This process is a key aspect of sexual reproduction.

Question 47

What is the normal range for human body temperature?

Answer 47

36.5˚C - 37.5˚C

Question 48

What happens when body temperature is low?

Answer 48

Temperature receptors in hypothalamus stimulate heat-producing mechanism ## Footnote This includes constriction of superficial arteries and increased shivering.

Question 49

What mechanisms are activated when body temperature is high?

Answer 49

Heat-releasing mechanism initiated by temperature receptors ## Footnote This includes vasodilation, sweating, and decreased metabolic heat production.

Question 50

What is osmoregulation?

Answer 50

Regulation of water and ion content in blood

Question 51

What is the primary function of the kidneys?

Answer 51

Osmoregulation, excretion, hormone production, filtering blood

Question 52

What occurs during ultrafiltration in the kidneys?

Answer 52

Blood plasma is filtered through the fenestration and basement membrane of the Bowman’s capsule

Question 53

Where does reabsorption occur in the kidney?

Answer 53

In the proximal convoluted tubule (PCT)

Question 54

What substances are reabsorbed in the PCT?

Answer 54

Glucose, amino acids, water, ions

Question 55

What is the role of the Loop of Henle in the kidneys?

Answer 55

Maintains hypertonic environment in medulla

Question 56

What is the function of ADH in osmoregulation?

Answer 56

Causes aquaporins to switch locations to increase water reabsorption

Question 57

What is natural selection?

Answer 57

Process where favourable variation increases in population across generations

Question 58

What are the key components of natural selection?

Answer 58

* Variation * Overproduction * Competition * Inheritance * Adaptation

Question 59

What is the difference between primary and secondary succession?

Answer 59

* Primary succession: occurs in an area never colonized * Secondary succession: occurs in an area previously colonized but disturbed

Question 60

What is a keystone species?

Answer 60

Species with a disproportionate effect on a community compared to their abundance

Question 61

What are density-dependent factors?

Answer 61

Factors that depend on population density

Question 62

What is ecosystem stability?

Answer 62

Ability to maintain structure and function despite disturbances

Question 63

What is the significance of genetic diversity in ecosystems?

Answer 63

High diversity makes ecosystems resistant to change

Question 64

What is biomagnification?

Answer 64

Accumulation of pollutants in higher trophic levels through the food chain

Question 65

What is the impact of eutrophication?

Answer 65

Causes algal blooms, increases BOD, and decreases sunlight availability for aquatic plants

Question 66

What are anthropogenic causes of climate change?

Answer 66

Greenhouse gas emissions from fossil fuel combustion and deforestation

Question 67

What is a positive feedback cycle in climate change?

Answer 67

A cycle where initial changes cause further changes that amplify the effect

Question 68

What is phenology?

Answer 68

Study of the timing of biological events in relation to seasonal and environmental factors

Question 69

What are the effects of climate change on migration patterns?

Answer 69

Alters environmental cues leading to mismatched timing in species

Question 70

What is the effect of microplastics on marine life?

Answer 70

Can degrade habitats and accumulate toxins in food chains

Question 71

What is the role of brown adipose tissue in thermoregulation?

Answer 71

Generates heat through uncoupled cellular respiration

Question 72

Fill in the blank: The absence of a ________ species can drastically alter an ecosystem.

Answer 72

keystone

Question 73

True or False: Only mutations in somatic cells are inheritable.

Answer 73

False