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Cell Bio ch 5
| Question | Answer |
|---|---|
| DNA ---> RNA ---> protein | Gene ---> mRNA ---> polypeptide |
| DNA (gene) ---> RNA (mRNA) is known as what? | Transcription |
| RNA (mRNA) ---> protein (polypeptide) is known as what? | Translation |
| What is the genetic material? | DNA |
| What is all of the DNA in the cell referred to as? | Genome |
| Passed from one generation to the next; gives us our particular characteristics | Genome |
| Specific segments (sequences) of DNA; provide instructions | Genes |
| DNA gets copied into identical DNA molecules during _____ (prep for cell division) | Replication |
| A gene is used to make an RNA molecule | Transcription |
| One strand of DNA is _____ to make two identical strands | Copied |
| Copy of a structural gene | mRNA |
| Will be used by ribosomes as directions for making a specific protein | mRNA |
| Copy of a tRNA gene | tRNA |
| Involved in process of translation (carries amino acids to the ribosome) | tRNA |
| Copy of an rRNA gene | rRNA |
| Makes up part of the ribosome | rRNA |
| The specific sequence of nucleotides in an mRNA is "read" by what? | Ribosome |
| The sequence of nucleotides determines the sequence of _____ _____ in the protein | Amino acids |
| DNA is useful as the genetic material mainly because of its _____; easy to copy | Structure |
| DNA consists of two chains of nucleotides, which form what? | Double helix |
| Single ring containing C and T | Pyrimidine |
| Double ring containing A and G | Purine |
| What is the sugar in DNA? | Deoxyribose |
| DNA is made up of a _____ ring, _____, and a _____ group | Nitrogenous ring, sugar, phosphate group |
| The backbone of DNA is what? | Phosphate-sugar |
| The bases in DNA hang off what? | The backbone |
| How many hydrogen bonds do A and T form? | Two |
| How many hydrogen bonds do G and C form? | Three |
| The two nucleotide bases pair by _____ bonding | Hydrogen |
| What holds the two DNA strands together? | Hydrogen bonding between the bases |
| If the sequence of two strands of DNA is such that they can H-bond along their full length, then they are _____ | Complementary |
| A on one chain, T on the other; G on one chain, C on the other | Complementary |
| Each strand of DNA is directional, which is based on linkage of _____ _____ units (backbone) | Sugar-phosphate |
| Free phosphate group on 5' carbon | 5' end |
| The 5' end has a free _____ group on the 5' carbon | Phosphate |
| Free hydroxyl group on 3' carbon | 3' end |
| The 3' end has a free _____ group on the 3' carbon | Hydroxyl |
| The two complementary strands in a double helix run in opposite directions, thus making them what? | Anti-parallel |
| How many base pairs are in one full turn of the helix? | 10 |
| There are _____ Angstroms per base pair (rise) | 3.4 |
| There are _____ Angstroms per turn (rise) | 34 |
| Bigger indentation in DNA | Major groove |
| Smaller indentation in DNA | Minor groove |
| Eukaryotes have many _____ chromosomes | Linear |
| DNA + histones + other associated proteins | Chromatin |
| What kind of chromosomes are very long and wrapped around proteins (histones) and packaged in an orderly fashion? | Eukaryotic |
| Usually has one circular chromosome | Bacteria |
| Not nearly as long as eukaryotic chromosomes; associated with proteins (but not histones) | Bacterial chromosome |
| Chromosome lengths range from _____ million to _____ million base pairs long | 50, 250 |
| How many base pairs are in one copy of the human genome? | 3.2 x 10^9 |
| How many copies of the human genome do we have? | Two |
| The entire genome, stretched out, would be about _____ meters long (this is in EVERY cell) | Two |
| Entire complement of genetic material in an organism (billions of base pairs) | Genome |
| Individual, linear segments (millions of base pairs) | Chromosome |
| Humans have _____ individual chromosomes and two copies of each, giving us a total of _____ chromosomes | 23, 46 |
| Smaller segments (portions) of chromosomes (thousands of base pairs) | Gene |
| Approximately how many genes do humans have? | 25,000 |
| Humans have 22 different _____ | Autosomes |
| Chromosomes that don't determine sex; we have two copies of each (one from mom, one from dad) | Autosomes |
| Are autosomes haploid or diploid? | Diploid |
| Humans have 2 _____ chromosomes | Sex |
| XX are the sex chromosomes for... | Females |
| XY are the sex chromosomes for... | Males |
| Two pairs of each chromosome are called _____ chromosomes | Homologous |
| Contain the same genes although they may be different versions | Homologous chromosomes |
| What are the only chromosomes that are not homologous (different genes)? | X and Y |
| A display of the full set of 46 chromosomes (can look for large abnormalities) | Karyotype |
| Prepared using cells in mitosis; chromosomes are stained in a variety of ways to aid identification | Karyotype |
| One chromosome breaks and attaches to the end of another | Translocation |
| More than two copies of a chromosome | Trisomy |
| There is some correlation between organism complexity and _____ _____ (but only on a larger scale) | Genome size |
| Eukaryotic genomes are usually much _____ than bacterial genomes | Bigger |
| Our genome is much _____ than some plants and amoeba | Smaller |
| There is no real _____ between gene number, genome size, and chromosome number (genomes can contain a few long chromosomes or many short ones) | Correlation |
| Bacteria and most unicellular organisms have very _____ genomes | Compact |
| Eukaryotes have lots of _____ in between genes, frequently called "junk DNA" | Space |
| Many scientists believe the sequence isn't important, but the spacing is | Junk DNA |
| During the cell cycle: everything except mitosis | Interphase |
| Dispersed chromosomes (less condensed); individual chromosomes can't be distinguished using a light microscope | Interphase |
| Chromosomes are very condensed; can see individual ones | Mitosis |
| Specialized area of a chromosome necessary for separation during mitosis | Centromere |
| Place where DNA copying starts; there are many on each eukaryotic chromosome | Origin of replication |
| End of the chromosome; allows the ends to be replicated and also provides a "cap" that marks the ends as ends (rather than breaks) | Telomere |
| During interphase, regions with genes that are expressed are _____ condensed; proteins and other enzymes involved in gene expression need access! | Less |
| Regions with genes that are silent are _____ condensed; no access needed | More |
| Nucleotide sequence of DNA that control a discrete hereditary characteristic of an organism | Gene |
| Encodes an RNA molecule (rRNA, mRNA, tRNA, etc.) | Gene |
| How many nucleotides are usually in one gene? | 1 x 10^4 to 5 x 10^5 |
| Double membrane that surrounds the nucleus | Nuclear envelope |
| Channels through the nuclear envelope | Nuclear pores |
| Allow some molecules to pass through nuclear envelope; passage is regulated | Nuclear pores |
| Fibrous network of proteins lining the inside of the nuclear membrane | Nuclear lamina |
| Gives structural support for the nuclear membrane | Nuclear lamina |
| Abnormal nucleus shape is present in patients with mutations in _____ _____ proteins (causes disease called progeria) | Nuclear lamina |
| Chromosomes occupy _____ locations in the nucleus; very organized | Discrete |
| Area where genes for ribosomal RNA cluster (rRNA is synthesized) | Nucleolus |
| The DNA has to be packaged in specific structural units in order to fit inside the _____ | Nucleus |
| Stretched out, the DNA in our cells would be about _____ meters long | Two |
| The nucleus is usually less than _____ micrometers | 10 |
| DNA is condensed through association with _____ proteins | Histone |
| What are the two types of associated proteins in chromatin? | Histones, non-histone proteins |
| DNA is highly _____ to allow it to fit in the nucleus | Condensed |
| What are the five main histones? | H1, H2A, H2B, H3, H4 |
| Huge levels of expression; extremely highly conserved | Histones |
| What histones make up a histone octamer? | H2A, H2B, H3, and H4 (two of each) |
| DNA is wrapped around the _____ _____ | Histone octamer |
| Histones have a high proportion of _____ and _____ | Lysine, arginine |
| In histones: being positively charged amino acids, they bind to the negatively charged Pi groups that are more abundant in DNA | Lysine, arginine |
| The DNA makes _____ turns around the histone octamer | 1.7 |
| How many base pairs of DNA are wrapped around each histone octamer? | 146 |
| The DNA and histone octamer complex is known as... | Nucleosome core particle |
| DNA molecule wrapped around a histone octamer plus the linker region (DNA in between the histones) | Nucleosome |
| Regions of RNA in between nucleosome core particles | Linker region |
| How many base pairs are typically in linker DNA? | Can vary - usually a few to 80 base pairs |
| An enzyme that digests (cuts) DNA | Nuclease |
| Short digestion times: nuclease breaks down only _____ region, which frees individual nucleosome core particles | Linker |
| Region of core histones that extend out of the nucleosome | Histone tails |
| N-terminal end; subject to many COVALENT modifications (methylation, phosphorylation, ubiquitination) | Histone tails |
| Areas with no genes (centromeres and telomeres) are very highly _____ | Compacted |
| What is the first level of compaction of DNA? | Formation of nucleosomes |
| The formation of nucleosomes reduces the length of DNA to about _____ | 1/3 |
| HISTONES: also known as "linker" histone | H1 histone |
| HISTONES: binds the linker region in between nucleosome core particles | H1 histone |
| HISTONES: thought to bring individual nucleosome core particles together | H1 histone |
| HISTONES: aids in further compaction of DNA | H1 histone |
| What is the second level of compaction of DNA? | 30 nm fiber |
| Individual nucleosomes packed close together | 30 nm fiber |
| Thought to be mediated by histone H1 | 30 nm fiber |
| The 30 nm fiber is folded into a series of _____ | Loops |
| The 30nm fiber folding into a series of loops is probably mediated by attachment of specific regions to _____ _____ or _____ _____ | Nuclear envelope, nuclear lamina |
| DYNAMIC CHROMATIN STRUCTURE: unfold enough for RNA polymerases and associated proteins to get in | Gene expression |
| DYNAMIC CHROMATIN STRUCTURE: unfold enough for DNA polymerases and associated proteins to get in | Replication |
| DYNAMIC CHROMATIN STRUCTURE: other times, proteins need access to _____ DNA damage | Fix |
| Protein machines that modify DNA structure | Chromatin remodeling complexes |
| Chromatin remodeling complexes use energy from ATP _____ to push on the nucleosomes | Hydrolysis |
| The overall result of chromatin remodeling complexes is that nucleosomes are _____ | Repositioned |
| Decreases compaction; exposes areas of DNA to other proteins | Chromatin remodeling complexes |
| Reversible COVALENT modification; N-terminus | Histone tail modification |
| Phosphorylation, acetylation, methylation done by enzymes present in the nucleus | Histone tail modification |
| RESULTS OF HISTONE MODIFICATION: "_____" positive charges on the histone tails (might make 30nm fiber less tightly packed) | Neutralizes |
| RESULTS OF HISTONE MODIFICATION: acts as a _____ (modified histones are recognized and bound by various proteins) | Code |
| RESULTS OF HISTONE MODIFICATION: sometimes used to "_____" regions of chromatin (newly replication, etc.) | Tag |
| Modification state of histones, in general, doesn't indicate whether a region will be tightly compacted; depends on the specific modification present and the combinations | Histone code |
| Modification state of histones depends on the activity of the modifying _____; these are usually signaled by other things going on in the cell | Enzymes |
| Histone acetylation state is determined by what two things? | Histone acetyltransferases (HATs) and histone deacetylases (HDACs) |
| Chromatin remodeling complexes and histone modifying enzymes are tightly _____ | Regulated |
| Processes in regulation are _____, allowing cell to modify chromatin structure, as needed | Reversible |
| Usually doesn't contain any genes; stains dark; usually ~10% of a chromosome | Heterochromatin |
| Centromeres, telomeres, and the inactive X chromosome (in females) are examples of what type of chromatin? | Heterochromatin |
| Everything that's not heterochromatin is... | Euchromatin |
| _____ chromosomes exhibit different levels of compaction in different regions (areas with genes expressed = less compact, areas with silent genes = more compact) | Interphase |
| Areas present as heterochromatin usually do not contain _____ | Genes |
| Tends to spread; modified regions attract enzymes that modify histone tails in adjacent regions | Heterochromatin |
| Associated with specific histone tail modifications; methylation of lysine (K) 9 on H3 | Heterochromatin |
| When heterochromatin spreads, nearby genes are subjected to _____ _____ | Positive effects |
| Chromatin structure can be inherited; histones from parent chromosomes are deposited onto daughter chromosomes during replication (meaning daughter chromosomes each get 1/2 "marked" histones) | Inherited |
| Marks on genome (DNA/chromatin) that affect gene expression but DO NOT change the DNA sequence | Epigenetic inheritance |
| _____ modifications are one type of epigenetic regulation and inheritance | Histone |
Created by:
stephanielynhannigan