Biology Chapter on Enzymes and Protein Synthesis

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What occurs at the A-site during protein synthesis?

The formation of a glycosidic bond

The exit of tRNA from the ribosome

The attachment of the polypeptide to the ribosome

The release of the amino end of an amino acid (correct)

During gated transport, which of the following processes occurs?

Import into mitochondria

Translocation into the endoplasmic reticulum

Export from the cytoplasm

Import into the nucleus (correct)

Which transport process is involved in returning proteins from the Golgi to the ER?

Transmembrane transport

Passive diffusion

Vesicular transport (correct)

Gated transport

What is the pH level commonly maintained by lysosomes?

Highly acidic, around 2.0 to 2.5 (B) Signup and view all the answers

Which mechanism is used for import into mitochondria?

Transmembrane transport (B) Signup and view all the answers

What is one characteristic of lysosomal membrane proteins?

They are heavily glycosylated (B) Signup and view all the answers

What is a key feature of vesicular transport?

It allows movement between membrane-enclosed organelles (C) Signup and view all the answers

Which process is NOT a function of the endoplasmic reticulum?

Cellular digestion (A) Signup and view all the answers

What is the primary function of the telomerase enzyme in human cells?

Extends telomeres using an RNA template (A) Signup and view all the answers

What process occurs at the restriction point in the mammalian cell cycle?

Commitment to DNA replication (B) Signup and view all the answers

During which phase of meiosis do sister chromatids separate?

Meiosis II (B) Signup and view all the answers

What characterizes strand A in the replication fork?

It is called the lagging strand (C) Signup and view all the answers

Which of the following statements is NOT true about the functions of telomerase?

It directly repairs damaged DNA (A) Signup and view all the answers

In which phase of the cell cycle does the restriction point occur?

Late G1 phase (D) Signup and view all the answers

What happens during Meiosis I and Meiosis II?

Homologous chromosomes separate in Meiosis I (C) Signup and view all the answers

What is the direction of synthesis for the newly formed strand in DNA replication?

From 5′ to 3′ (A) Signup and view all the answers

Which enzyme synthesizes RNA using one of the DNA strands as a template?

RNA polymerase (D) Signup and view all the answers

What type of bond is formed between the carboxyl group of the amino acid and the tRNA during activation?

Ester bond (B) Signup and view all the answers

When reading mRNA during translation, in which direction does the ribosome move?

5' to 3' (B) Signup and view all the answers

Which end of the polypeptide chain is elongated during protein synthesis?

C-terminus (C) Signup and view all the answers

What occurs during the peptidyl transfer step in elongating ribosomes?

The carboxyl end of the polypeptide is joined to the A-site tRNA. (A) Signup and view all the answers

Which of the following accurately describes the role of aminoacyl-tRNA synthetase?

It attaches amino acids to their corresponding tRNAs. (A) Signup and view all the answers

What is the result of the high-energy bond formed during the attachment of the amino acid to the tRNA?

It facilitates the peptide bond formation. (A) Signup and view all the answers

During translation, the mRNA is read in sets of how many nucleotides?

3 nucleotides (B) Signup and view all the answers

Which statement is true regarding the inheritance of affected individuals in genetics?

An affected woman almost always has an affected mother. (D) Signup and view all the answers

What process is responsible for generating genetic variation in offspring?

Crossing over and independent assortment. (B) Signup and view all the answers

In the Hershey and Chase experiment, which isotope was used to label the viral protein?

Sulfur-35 (B) Signup and view all the answers

Which structures contain repetitive DNA and heterochromatin?

Both telomeres and centromeres (D) Signup and view all the answers

Which enzyme does not assist in unwinding DNA for replication?

Primase (A) Signup and view all the answers

What would be the mRNA sequence transcribed from the DNA template 5′ GTACCGTC 3′?

5′ GACGGUAC 3′ (B) Signup and view all the answers

How do nonsense mutations affect protein synthesis?

They convert a codon for an amino acid into a stop codon. (B) Signup and view all the answers

Which group of functional groups is present in the amino acid serine at neutral pH?

Amino, carboxyl, and hydroxyl groups. (B) Signup and view all the answers

What term describes a form of a gene with a slightly different sequence that encodes the same type of RNA or protein?

allele (D) Signup and view all the answers

What is the attachment point on the chromosome for spindle microtubules during cell division?

centromere (A) Signup and view all the answers

Diploid cells are characterized by having how many sets of chromosomes?

two sets (A) Signup and view all the answers

During which phase do microtubules attach to the kinetochores?

prometaphase (B) Signup and view all the answers

In a cross between a pure-breeding yellow plant and a pure-breeding green plant, what is the expected proportion of green-seeded plants in the offspring of a yellow offspring crossed with a green plant?

50% (C) Signup and view all the answers

Which of the following chromosome constitutions cannot lead to a viable human baby?

YY (D) Signup and view all the answers

If one parent has blood type AB and the other has blood type A, which blood types can their children possibly inherit?

A, B, and AB only (A) Signup and view all the answers

Which statement is inaccurate regarding X-linked recessive traits in humans?

All sons of an affected woman are expected to be affected. (D) Signup and view all the answers

Study Notes

Enzyme Depicted in Schematic Drawing

The enzyme depicted in the schematic drawing is RNA polymerase
RNA polymerase synthesizes RNA using one strand of DNA as a template

Aminoacyl-tRNA Synthetase

Aminoacyl-tRNA synthetase activates amino acids by attaching them to tRNA(s)
The linkage between the amino acid and tRNA occurs between the carboxyl group of the amino acid and the 3' or 2' hydroxyl group of the tRNA
The amino group of the amino acid acts as the attacking group in peptide bond formation

mRNA Reading and Polypeptide Synthesis

mRNA is read from 5' to 3' on the ribosome
Polypeptide synthesis occurs from the N-terminus to the C-terminus

Elongating Ribosome

An elongating ribosome bound to appropriate tRNAs in the A and P sites is ready for peptidyl transfer
The carboxyl end of the polypeptide chain is released from the P-site tRNA and joined to the free amino group of the amino acid linked to the A-site tRNA

Transport Processes

Import into nucleus (G)
Export from nucleus (G)
Import into mitochondria (T)

Lysosomes

Lysosomes are the principal site of cellular digestion
Lysosomes maintain a pH of about 2.0 to 2.5
Lysosomes contain F-type ATPases that pump protons into the organelles

Telomerase Enzyme

Telomerase has an RNA component
Telomerase extends the telomeres using its RNA component as a template
Telomerase polymerizes DNA sequences at chromosome ends to solve the "end-replication" problem

Replication Fork

The strand labeled A in the replication fork schematic is called the lagging strand

Restriction Point

The restriction point in the mammalian cell cycle is represented by time point B

Meiosis Division Similar to Mitosis

Meiosis II is more similar to mitosis
Sister chromatids separate in meiosis II

Gene Form

A form of a gene with a slightly different sequence but encoding the same RNA or protein is called an allele

Chromosome Attachment Point

The attachment point of spindle microtubules on the chromosome is the centromere

Diploid Cells

Diploid cells have two sets of chromosomes

Prometaphase

Microtubules attach to the kinetochores during prometaphase

Mendelian Genetics

In Mendel's peas, yellow seeds are dominant to green
If a yellow pea plant (homozygous dominant) is crossed with a green pea plant (homozygous recessive), all offspring will be yellow
Breeding a yellow offspring (heterozygous) with a green plant gives a 50% chance of green offspring

Chromosome Constitutions

XXY, XXX, and XYY are all viable human chromosome constitutions

Codominance and Blood Types

In humans, blood types A and B are codominant to each other and each is dominant to O
Offspring from an AB and A blood type parent can result in A, B, and AB blood types

X-linked Recessive Traits in Humans

An affected man often has phenotypically normal parents
All the sons of an affected women will be expected to be affected.
An affected man usually has a mother who carries the recessive allele
A phenotypically normal woman whose father was affected is likely to be heterozygous for the condition

Recombination

Recombination occurs through crossing over and independent assortment

Hershey-Chase Experiment

Hershey and Chase used 35S to label the viral protein

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

This quiz covers essential topics related to enzymes, specifically RNA polymerase and aminoacyl-tRNA synthetase, along with the processes of mRNA reading and polypeptide synthesis. It explores how these molecules interact during protein synthesis and their roles in translation. Test your understanding of these critical concepts in molecular biology.