Biology Exam Questions PDF

Biology exam questions 1. Which of the following features of the metaphase chromosome is not a morphological feature of the chromosome? Banding pattern Position of the centromere **Number of chromosomes** Chromosome length 2. What compounds does tRNA transport? Peptides **amino acids**...

Biology exam questions 1. Which of the following features of the metaphase chromosome is not a morphological feature of the chromosome? Banding pattern Position of the centromere **Number of chromosomes** Chromosome length 2. What compounds does tRNA transport? Peptides **amino acids** codons Proteins 3. What interactions are not involved in the formation of the tertiary structure of RNA?: Creation of an A-type helix Interactions of arm stems with other arm stems **Binding of basic proteins or ions that neutralize the negative charge of RNA** Formation of non-canonical pairs or triplets 4. What characterizes the pseudouridine loop, or T-loop, of tRNA?: **It contains the site where the tRNA binds to the ribosome** Contains a D loop containing dihydrouridine mobilizes tRNA during the process of protein synthesis Contains an unpaired CCA sequence at the 3\' end 5. Which type of receptors are designed for neurotransmitters when a rapid response is necessary?: \* **ionotropic (ion-channel-coupled) receptors** receptors for lipophilic metabotropic hormones catalytic receptors G-proteins coupled receptors 6. What process causes the elongation of DNA replication to become an irreversible process?: Release of PPi from the nucleotide **Hydrolysis of pyrophosphate (PPi) to inorganic phosphate PP** Loss of ATP as an energy source Connection of the new thread to the matrix thread 7. What is combinatorial control of gene expression?: \* This is a process that involves the use of a single transcriptional regulator for normal gene expression **This is a process that involves the use of a group of transcriptional regulators working together to express a gene correctly** This is a process for which the use of only a gene activator is sufficient for proper gene regulation This is a process that involves only genes arranged in operons 8. What is Mitogen-activated Protein Kinase (MAPK)?: \* **The final serine-threonine kinase following the activation of Ras protein** Binding to the GEF protein and formation of a complex that is involved in the exchange of GDP for GTP in the Ras protein The result of dephosphorylation of serine and threonine residues from other kinases The attachment of the adaptor protein to a tyrosine residue 9. What element, apart from protein, can be a component of a glycoprotein?: \* Lipids Metal ions **Oligosaccharides** Phosphoric acid molecules 10. How do we define carbohydrates that are made up of more than 10 subunits?: \* Disaccharides **Polysaccharides** Oligosaccharides Monosaccharides 11. How are HSCs collected via apheresis?: \* **Using fluorescent antibodies selective for the CD34 surface protein** Bone marrow collection from the plate of the hip bone Enzymatic digestion of the collected material Cell expansion on culture medium 12. What kind of bonds form between the codon-anticodon bases?: \* Covalent bonds **Hydrogen bonds** Phosphodiester bonds Electrostatic interactions 13. In which segment of the lipid bilayer are its hydrophobic components contained?: \* **Inside the lipid bilayer** All answers are incorrect On the inner surface of the lipid bilayer On the outer surface of the lipid bilayer 14. What DNA repair process involves the MGMT protein, which removes the oxygen-bound methyl group O6 of guanine?: \* **Direct repair (DR)** Base Cutting Repair (BER) Mispaired nucleotide (MMR) repair Nucleotide excision repair (NER) 15. What histone protein does not form part of the nucleosome core?: \* H3 **H1** H4 H2A 16. In which phase of the cell cycle is the concentration of mitotic cyclin (cyclin B) the highest?: \* In phase S **In phase M** In phase G1 In phase G0 17. Under what conditions does programmed cell death (apoptosis) occur?: \* It occurs only during embryonic development **when the activation of a cell-death intracellular program is initiated** During gametogenesis when the body is under stress No energy is needed 18. How many basic amino acids are found in human proteins?: \* **6** 20 32 10 19. What kind of secondary structure of a protein is stabilized by the hydrogen bond between the NH and CO of the amino acid residue i and i+3?: \* Parallel β-sheets **β-turns** Anti-parallel β-sheets α-Helix 20. Interphase is the phase of the cell cycle that the cell is in for the majority of the time. What phases does it include? \* **G1, S, and G2 phases altogether** mitosis only S phase, G2 phase, and mitosis G1 and S phase only 21. What step does not occur during nucleotide excision repair?: \* Cutting the DNA strand on both sides of the damage by XPG and XPF endonucleases **Removal of the damaged nitrogenous base by specific DNA glycosylase** Synthesis of a new DNA strand fragment by β polymerase Unraveling of the double strand around the damaged nucleotide by helicases 22. What is a chromosome considered when its arms are equal in length?: \* Submetacentric **Metacentric** Acrocentric Telocentric 23. In which phase of mitosis do the sister chromosomes separate?: \* In prometaphase In prophase In metaphase **In anaphase** 24. What is the smallest living unit on Earth?: \* an Organelle **the Cell** Protein DNA 25. What areas do chromosomes occupy in a cell between divisions?: \* **They occupy distinct areas in the interphase nucleus** They have the same nuclear territory as their homologue They are limited to the nucleolus They are completely entangled with other chromosomes 26. In which structure of RNA do apical loops (hairpins) exist? \* Tertiary structure of RNA Primary RNA structure Quaternary structure of RNA **Secondary RNA structure** 27. Which type of membrane transport is the sodium-potassium pump classified as?: \* **Primary active transport** Facilitated diffusion Simple diffusion Secondary active transport 28. The secondary lysosome is a result of the combination of: \* a primary lysosome with a macrophage **a primary lysosome with a phagosome** a primary phagosome with a peroxisome the endoplasmic reticulum with a vesicle 29. What happens when an mRNA attaches to a ribosome? \* A conformational change to the large subunit to bind to the ER the sedimentation rate of the subunit changes from 50S to 70S **the large subunit and small subunit become conjoined to begin translation** the large subunit and small subunit separate to begin translation 30. What functions do lysosomes perform in the cell?: \* **Break down of carbohydrates, proteins, fats and nucleic acids** Sorting of transport vesicles Transport of materials to the Golgi apparatus Storage of excess macromolecules 31. In interphase, heterochromatin: \* is genetically inactive **all answers are correct** stains dark under a microscope is in a condensed state 32. For which ligands are \"orphan\" receptors intended?: \* **unknown ligands** active vitamin D3 (1,25-dihydroxyvitamin D3) active vitamin A (retinol) lipophilic hormones 33. Where does the electron transport chain occur? \* the nucleus **the inner membrane of the mitochondria** the cytoplasm the mitochondria 34. What type of membrane transport is associated with the formation of a phagosome?: \* secondary active transport receptor-mediated endocytosis pinocytosis **phagocytosis** 35. How many times does interphase DNA shorten into metaphase chromosomes?: \* **10,000x** 100,000x 100x 1,000x 36. What compound is necessary for aerobic respiration in which the cell breaks down macromolecules stepwise for energy in the form of ATP? \* Nitrogen Guanine Sulfur **Oxygen** 37. In which DNA condensation process is histone H1 directly involved?: \* Chromatin in the \"string of beads\" formation Interphase chromatin formation **formation of the 30nm fiber** Creating DNA loops 38. What type of ligands are transported through the circulatory system?: \* only neurotransmitters, like adrenalin (epinephrine) **neurotransmitters and hormones, like adrenalin (epinephrine)** only hormones, like adrenalin (epinephrine) none of the answers include ligands transported through the circulatory system 39. Which of the following phospholipid movements may be catalyzed by enzymes in the cell membrane?: \* **Transverse "flip-flop" movement** Flexion Lateral diffusion Rotational motion 40. What is a codon?: \* Three nucleotides of DNA **Three nucleotides of RNA** Three amino acids Three DNA nucleotides or 3 RNA nucleotides 41. How is the START codon recognized in eukaryotes during translation initiation?: By binding tRNA By recognizing the ATC codon as the origin of translation **Through the binding of the small unit of ribosome, mRNA and initiator tRNA** By scanning along the mRNA from the 5\' end 42. Which of the following is a component of a glycolipid?: \* insulin **sphingosine** guanine none are components of a glycolipid 43. **Which of the following DNA strands can form a DNA duplex by pairing with itself at each position?** A. 5'-AAGCCGTT-3' B. 5'-AAGCCGAA-3' C. 5'-AAGCGCAA-3' D. **5'-AAGCGCTT-3'** EDTA- blood clotting prevent **Midori green?** Stains the DNA Makes us follow the gel electrophoresis process Toxic a helix pcr mitochondria in humans cell pcr temperature membrane structre deoxyrublionucleous made of? agarose made of? lipid rafts types of chromosomes autosomes and allosomes cristae ER centrosomes kinetochore how much water in cell positive control PCR stem cells interphase cell signaling - junxacrina CDC Phases of meiosis liptone stem cell - satellite cells **The course of the cell cycle is determined by?** A. Protein kinases dependent on membrane protein and lipids B. Cyclins dependent on spindle tubulin proteins C. **Cyclin-dependent protein kinases (cdk), as cell cycle kinases become enzymatically active due to the attachments of cyclins** D. None of the above **Mitogens?** A. Proteins that regulate mitosis B. Genes responsible for the normal course of mitosis and cell division C. **Extracellular signal molecules that stimulate cell proliferation** D. Intercellular signals that stimulate the production of cyclins, which stimulates cell division **6 pcr cycles** 64 **Sodium-potassium pump** type of transport- primary active **what type of blabal is blabal with kjønnsceller og extra embryo** totihypotent/omnihypotent- embryonic stem cells **Proteinkinase K destroys** phospholipids **What is the structure of DNA?** is a polymer of nucleotides. Each nucleotide is composed of a nitrogenous base, a five-carbon sugar (deoxyribose), and a phosphate group. There are four nitrogenous bases in DNA, two purines (adenine and guanine) and two pyrimidines (cytosine and thymine). A DNA molecule is composed of two strands. **Amino acid structure:** Amino acids are the monomers that make up proteins. Each amino acid has the same core structure, which consists of a central carbon atom, also known as the alpha (α) carbon, bonded to an amino group (NH2), a carboxyl group (COOH), and a hydrogen atom. **Amino acid backbone?** - **The backbone, when ignoring the hydrogen atoms, consists of the pattern:** - **N-C-C** **How many amino acids in one natural protein?** - **20** **What is the concentration of RNA in a cell?** - **10-20** **What is the most dominant part of RNA in a cell?** - **rRNA makes up about 70-80% of all RNA** **What is the concentration of potassium and natrium in cell?** - **pottasium: intracellular, natrium; extracellular** **What does cholesterol do with the cell?** - **holds phospholipids together, so they can not move** **Positive control PCR?** - A positive control is a known DNA sample that has been previously typed and is added to the sample set. The positive control verifies that the analysis processes are functioning properly. (Manufacturers provide positive control samples in STR kits What is cellular respiration? - Cellular respiration is a metabolic pathway that breaks down glucose and produces ATP. cellular respiration? - Hydrolysis- krebs cycle- electron chain What does a long carbon chain do? - make it less soluble the carbohydrate is in water What is carbohydrate with more than 10 molecules? - polysaccharide **What is carbohydrate with up to 10 molecules?** - oligosaccharide **What do ribosomes that freely float in cytoplasm do?** - freely float in the cytoplasm, which produce proteins that function in the cytosol. **What is amyloplast composed of?** - contain carbohydrates - in the form of starch grains **what is the first amino acid in all proteins produced by the mitochondria and by chloroplasts like in bacteria?** - N-formylmethionine **what happens if the annealing temperature is too high in PCR?** - the primers will not bind to the template. **What is the cytoplasm composed:** It is composed of water, salts, and various organic molecules. **what kind of protein structure does a protein bound with a sulfide bridge have?** - tertiary structure **Two rings?** Purines **one ring?** pyramidines Degeneracy - can encode for the same aminoacid (differs in 3 nucleotide) Types if amino acids chain cyclic OH group, Thiol group, amino group ### **Non-polar / hydrophobic:** **→ Aliphatic side chain** **→ Cyclic side chain** AMINOACID COMPONENTS Sub-classification of alpha-amino acids (expept glycine) based on spatial arrangement of amino group relative to the chiral / asymmetric carbon: **In addition - there is a pool of free protein amino acids** → Which have huge important biologial functions as: → Synthesis of lipids & their derivaties (serine, glycine) → Transmission of nerve signals (glutamic acid, aspartic acid) → Transmittsion of hormonal signals (tyrosine) ### **Including ß, γ & δ amino acids - most important non-protein AAs:** → **γ-aminobutyric acid (GABA):** main inhibitory neurotransmitter in nervous system → **Ornithine & citrulline:** intermediate matbolics of urea cycle **Peptide bond = formed by condensation reaction between:** \ ### **→ An amino group of one molecule** ### **→ A carboxyl group of other molecule** \ **The by-product = water molecule** ### **Occurs in 2 forms:** **→ Globular - G-actin** **→ Filamentous - F-actin** **Protein complexes** ===================== ### **Glycoproteins** \ **Contain covalently bound:** → Straight chain or → Branched oligosaccharides \ ### **Phosphoproteins** \ **Contain:** → Threonine or → Serine residues esterifies with phosphoric acid \ ### **Metalloproteins** \ **Contain:** Ions of various metals interacting with → Protein (either ionocally or by coordination) \ **Many organic coenzymes & prosthetic groups are vitamins or respective derivaties** → Essential for functions of body Checkpoint for separation of chromosomes - m-checkpoint - g1-checkpoint - g2-checkpoint ### **Characteristics:** → Require presence of a DNA template **→ Unable to start synthesis of a complimentary trand on DNA tempkkate - primer required** **2 types of tRNA that can bind methionine - one of which:** ### **→ Participates in initiation- met-tRNAm** ### **→ Participates in elongation- fmet-tRNAf**