Biology Chapter 14 Key Questions

What are some effects of mutations?

can cause the protein to malfunction or to be missing entirely. When a mutation alters a protein that plays a critical role in the body, it can disrupt normal development or cause a medical condition. can vary widely, from being beneficial to having no effect, to having lethal consequences, and every possibility in between.

What are point mutations?

chemical changes in just one base pair of a gene

What are deletion chromosomal mutations?

involves loss of all or part of chromosome

What do ribosomes do?

make proteins

What are inversion chromosomal mutations?

reverses direction of parts of chromosome

rRNA

ribosomal RNA, hold tightly to the mRNA and use its information to assemble amino acids

How do mutations affect genes?

Alter the gene expression by changing the proteins that are coded for. The effects of mutations on genes vary widely. Some have little or no effect; and some produce beneficial variations. Some negatively disrupt gene function.

Describe the ways mutations can affect DNA and chromosomes

Mutations present permanent and heritable changes in the genome. We distinguish gene and chromosome mutations. Mutations in the level of genes are called point mutations because only one to several nucleotides are changed. These processes are known as deletion, insertion, and substitution. Mutations can also appear in chromosomes altering their number and structure. There are four types of mutations - deletion, duplication, inversion, and translocation.

What do ribosomes do in transcription?

Ribosomes are the sites in a cell in which protein synthesis takes place. ... Within the ribosome, the rRNA molecules direct the catalytic steps of protein synthesis — the stitching together of amino acids to make a protein molecule. In fact, rRNA is sometimes called a ribozyme or catalytic RNA to reflect this function.

What role does the ribosome play in assembling the protein?

Ribosomes travel along strands of mRNA and provide sites for tRNA to attach according to the codon sequence. The amino acids form peptide bonds with the end of the polypeptide strand and the ribosomecontinues upstream.

Why are master control genes almost universal and common to different organisms?

The genetic code is considered universal because all organisms use the same genetic code.

What are insertion mutations?

The insertion of a nucleotide into a sequence along a DNA strand, all amino acids after this changed/affected

How do the three types of RNA work together at a ribosome to synthesize a polypeptide?

Transfer RNA (tRNA) is the key to deciphering the code words in mRNA. Each type of amino acid has its own type of tRNA, which binds it and carries it to the growing end of a polypeptide chain if the next code word on mRNA calls for it. ... Ribosomal RNA (rRNA) associates with a set of proteins to form ribosomes.

What is the genome of an organism?

entire genetic material of that organism

Where does transcription occur?

nucleus

What are translocation mutations?

occurs when part of a one chromosome breaks off and attaches to another

What are duplication chromosomal mutations?

produces extra copy of all or part of chromosome

What is gene regulation?

the ability to turn genes on and off

How does the genetic code work?

the code is redundant and some amino acids are specified by more than one triplet called a codon. each three nucleotides in a row count as a triplet and code for a single amino acid.

How is information in DNA passed to a molecule of mRNA? Describe the process

The DNA is read by RNA Polymerase which then makes an exact match of the non-coding strand of the DNA into a RNA molecule - messenger RNA or mRNA...which is then read and transcribed by the ribosome into a protein.

What is the role of RNA in the production of proteins?

assembling amino acids into proteins. ... Transfer RNA transfers each amino acid to the ribosome as needed by the code of the mRNA molecule. rRNA. Ribosomal RNA makes up the ribosomes and is used to assemble the proteins at the ribosome.

How are prokaryotic genes regulated?

the primary method to control what type of protein and how much of each protein is expressed in a prokaryotic cell is the regulation of DNA transcription. All of the subsequent steps occur automatically. When more protein is required, more transcription occurs. Therefore, in prokaryotic cells, the control of gene expression is mostly at the transcriptional level.

What is gene expression?

the process by which DNA directs the synthesis of proteins

What is translation?

the process of translating the sequence of a messenger RNA (mRNA) molecule to a sequence of amino acids during protein synthesis. The genetic code describes the relationship between the sequence of base pairs in a gene and the corresponding amino acid sequence that it encodes. RNA to protein

What are epigenetics?

the study of changes in organisms caused by modification of gene expression rather than alteration of the genetic code itself

tRNA

transfer RNA; type of RNA that carries amino acids to the ribosome

Where does translation occur?

cytoplasm

How are genes regulated in eukaryotic cells?

1) By binding DNA sequences in the regulatory regions of eukaryotic genes, transcription factors control the expression of this genes. 2) Some enhance transcription by opening up tightly packed chromatin. Others help attract RNA polymerase. Other block access to certain genes, like the repressor protein in prokaryotes. 3) On the promotoer, with multiple points

What are the three mechanisms by which transcription factors regulate eukaryotic gene expression?

1. They act as activators of transcription. This is through increasing the affinity of the RNA polymerase on the promoter 2. They could act as repressors. This way, when they bind to their active sites, they repress the binding of the RNA polymerase on the promoter 3. Transcription factors at one site could affect transcription of genes on another site on the DNA. The flexibility of the DNA (by forming loops) allows for this phenomenon.

How does a cell interpret the genetic code?

A cell interprets a genetic code by reading and interpreting each codon which corresponds to a single amino acid.

What controls the development of cells and tissues in multicellular organisms?

Differential gene expression as a cell differentiates from a stem state to a specialized one. The way that genes are expressed changes as a cell ages. It also has to do with cell-cell or environmental signaling. After fertilization (when an egg and sperm unite to create a zygote), there is a series of rapid cell divisions which results in a hollow ball of cells with 3 germ layers (mesoderm, endoderm, and ectoderm). The cells in these three layers later differentiate into all the tissues and organs of the body.

In what ways do mutations change genetic information?

Each DNA difference results from a mutation — ranging from single nucleotide changes, to small repeated units, to larger insertions and deletions. Some mutations generate novel changes that are starting points of evolution, and some are responsible for disease.

How are proteins and genes related?

Genes are transcribed into MRNA which undergo translation and turn into amino acids which then join together to create proteins. This process is called protein synthesis.

What controls transcription in prokaryotes?

One required DNA-protein interaction determines where transcription begins. It involves the DNA segment called the promoter and the protein RNA polymerase. When RNA polymerase binds to the promoter DNA, transcription can initiate a few bases away from the promoter site. Every gene must have a promoter or it cannot be transcribed.

How does molecular biology relate to genetics?

Genetic is a science that explores genes and their inheritance, while molecular biology studies DNA and RNA at a molecular level, which includes processes of replication, transcription, translation. The connection between these sciences lies in the fact that genetic material is contained in DNA and RNA molecules

How does the cell make RNA?

In transcription, segments of DNA serve as templates to produce complementary RNA molecules.

What are the possible ways that a mutation may affect an organism?

Mutations can affect an organism by changing its physical characteristics (or phenotype) or it can impact the way DNA codes the genetic information (genotype). When mutationsoccur they can cause termination (death) of an organism or they can be partially lethal.

What do ribosomes do in translation?

Ribosomes use the sequence of codons in mRNA to assemble amino acids into polypeptide chains. Each tRNA has an anticodon that is complementary to the codon on the mRNA strand. The ribosome positions the start codon to attract its anticodon.

How do ribosomes use mRNA and tRNA to assemble proteins?

Ribosomes use the sequence of codons in mRNA to assemble amino acids into polypeptide chains. The cytoplasm of the cell. Each tRNA has an anticodon whose bases are complementary to the bases of a codon on the mRNA strand. ... The ribosome joins the two amino acids—and breaks the bond between methionine and its tRNA.

Ribosomes

Ribosomes' function is to manufacture proteins. They do this in a process known as translation, which involves taking instructions encoded in messenger ribonucleic acid (mRNA) and using these to assemble proteins from amino acids.

What are the master control genes?

Sequences of DNA found in all animals- control formation of proteins necessary for large scale, embryonic development. (Morphogenesis) They code for big-scale traits like; head, tail, arms, wings, organs, etc.

What is transcription?

Transcription is the process of making an RNA copy of a gene sequence. This copy, called a messenger RNA (mRNA) molecule, leaves the cell nucleus and enters the cytoplasm, where it directs the synthesis of the protein, which it encodes.

What are deletion mutations?

When a random base is deleted from the DNA base sequence, all amino acids after this changed/affected

How does translation work?

mRNA leaves the nucleus and finds a ribosome tRNA, carrying an amino acid, matches its anticodon to the codon on the mRNA this continues and an amino acid chain is made when the mRNA reaches a stop codon, the matching tRNA releases the protein and synthesis is complete

mRNA

messenger RNA; type of RNA that carries instructions from DNA in the nucleus to the ribosome

How does transcription work?

segments of DNA serve as templates to produce complementary RNA molecules Information in DNA is transcribed on to Messenger RNA The information in mRNA is Translated into protein