Exam #3 from slideshow Flashcards
What are prokaryotes?
genomes small and circular
Where is the DNA in prokaryotes?
DNA in cytoplasm
What are eukaryote?
genome larger and linear
Where is DNA in eukaryotes
Located?
DNA is in the nucleus
what is the first step to Binary fission
- Circular bacterial DNA molecule attached by protien to inner surface of membrane
What is Binary fission
Prokaryotic cell division
Second step to binary fission
- DNA replication begins ; moves bi-directionally around the circular DNA
Third step to binary fission
- Newly synthesized DNA molecule also attaches to the inner membrane ; near attachment site to the parent molecule
fourth step to binary fission
The cell gets longer ; separating DNA molecules
fifth step to binary fission
Synthesis of new cell membrane ; cell division starts
sixth step to binary fusion
Parent and daughter cell seperate ; Synthesis completes
What are the two types of Eukaryotic cell division?
Mitosis and Meiosis
Primary function of Mitosis
asexual reproduction of somatic cells
Why Mitosis?
Tissues can grow and repair (cells male re move cells)
So organisms can reproduce a sexually
Primary function of meiosis
production of gametes
Whats a gametes
sperm and eggs
Why Meiosis?
So organisms can produce Sexually
Where does Mitosis take place?
All somatic cells
Where does Meiosis take place
specialized germ cells in gonads
What is the primary difference between prokaryotic and eukaryotic genomes?
Prokaryotic genomes are small and circular, while eukaryotic genomes are large and linear
Prokaryotic DNA is located in the cytoplasm, whereas eukaryotic DNA is found in the nucleus.
What is the process of prokaryotic cell division called?
Binary fission
In binary fission, DNA replication begins at a specific location and proceeds bi-directionally.
What are the two types of eukaryotic cell division?
- Mitosis
- Meiosis
Mitosis is for asexual reproduction of somatic cells, while meiosis is for the production of gametes.
What are the stages of interphase in the eukaryotic somatic cell cycle?
- G1: Pre-synthesis growth
- S: Synthesis of DNA via replication
- G2: Post-synthesis growth
Interphase is the phase before cell division.
What are homologous chromosomes?
Chromosomes that carry the same genes but may have different versions (alleles) of those genes
They have similar sizes and shapes.
What occurs during prophase of mitosis?
Chromosomes condense, and centrosomes produce microtubules that migrate to opposite poles
The mitotic spindle is composed of microtubules.
What is the outcome of mitosis?
Two identical daughter cells are produced
There is no reduction in chromosome number.
What is crossing over and when does it occur?
The exchange of genetic material between non-sister chromatids during prophase I of meiosis
This results in recombinant chromatids.
What are the main differences between meiosis and mitosis?
- Meiosis results in four haploid gametes
- Mitosis results in two diploid daughter cells
- Meiosis includes two rounds of division
Meiosis reduces chromosome number, while mitosis maintains it.
What are the phases of the cell cycle?
- G1 phase
- S phase
- G2 phase
- M phase
M phase includes both mitosis and cytokinesis.
What is the function of cyclin proteins in the cell cycle?
Cyclin proteins bind to and activate cyclin-dependent kinases (CDK) to control progression through the cell cycle
Cyclin-CDK complexes phosphorylate target proteins that promote cell division.
What is the role of the p53 protein in the cell cycle?
p53 inhibits the cell cycle when DNA damage is detected, allowing time for repair
It acts as a transcription factor to turn on genes that produce proteins inhibiting cell division.
True or False: Tumor suppressor genes promote cell division.
False
Tumor suppressor genes encode proteins that inhibit cell division.
What is the multiple mutation model for cancer development?
- Activation of oncogene
- Inactivation of tumor suppressor genes
- Development from normal cells to benign cancer to malignant cancer
Metastasis can occur when malignant cancer spreads to new sites.
Fill in the blank: The process of _______ produces haploid gametes.
Meiosis
This process is essential for sexual reproduction.
What is a genome?
All the genetic material in an organism
Which type of genomes are the smallest?
Viral genomes
How is genome size measured?
Number of nucleotides or base pairs (bp)
What is the size of the COVID-19 genome?
30,000 bp
What does MB stand for in genomic terms?
Megabase = 1 million base pairs
What is lateral gene transfer (LGT)?
Movement of genetic material between organisms other than by vertical transmission
What is the C value paradox?
The amount of DNA in a cell is not strongly related to the complexity of an organism
What are the three fundamental components of genomic research?
- Genome Sequencing
- Genome Assembly
- Genome Annotation
What is genomics?
An interdisciplinary field of biology focused on the structure, function, evolution, mapping, & editing of genomes
What is the Sanger method?
A chain termination method for DNA sequencing, commercialized in 1987
What is Next Generation Sequencing (NGS)?
A sequencing technology available since 2004 that allows high-throughput whole-genome sequencing
What is the primary purpose of Polymerase Chain Reaction (PCR)?
To amplify/replicate DNA
What are the steps involved in PCR?
- DNA sample
- dNTP (nucleotides)
- Primers
- Taq Polymerase
- Buffer solution
What is structural annotation in genome annotation?
Identification of genomic elements and their locations within the genome
What are noncoding DNA sequences?
Sequences that do not code for proteins but may have regulatory functions
What is a mutation?
Any change in the genetic material of an organism
What is the difference between somatic cells and germ cells regarding mutations?
Somatic mutations are not heritable; germ cell mutations are passed on to offspring
What is a single-nucleotide polymorphism (SNP)?
A substitution of a single nucleotide at a specific position in the genome present in a large fraction of the population
What is the role of short tandem repeat (STR) polymorphisms in DNA fingerprinting?
They provide a unique combination of alleles based on the number of repeats at each STR site
What is copy number variation (CNV)?
Variation in the number of copies of a particular region of the genome
True or False: Mutations are random and unrelated to their usefulness to the organism.
True
What can cause cystic fibrosis at the genetic level?
Nucleotide deletion mutations
What is a frameshift mutation?
A mutation caused by nucleotide insertion or deletion that alters the reading frame of the gene
What are the types of point mutations?
- Synonymous (silent) mutations
- Nonsynonymous (missense) mutations
- Nonsense mutations
What technique is commonly used to separate DNA fragments by size?
Gel Electrophoresis
What is the average size of a human protein-coding gene?
10,000-15,000 base pairs of DNA
What is the typical mutation rate in smaller genomes?
Higher mutation rates per cell cycle
What percentage of the human genome is due to copy number variation (CNV)?
5-10%
Fill in the blank: The process of identifying all organisms in an environmental sample is known as _______.
Metagenomics
What is the role of genomic annotation?
Attaching biological information to genomic elements
What is genetic variation?
Genetic differences that exist among individuals in a population at a particular point in time
This concept is essential in understanding how traits are inherited and expressed.
Define genotype.
The genetic makeup of a cell or organism
The genotype determines the potential traits that can be expressed.
What is a gene?
Segment of DNA that codes for a protein
Genes are the basic units of heredity.
What are alleles?
Alternate versions of a gene
Alleles can be dominant or recessive.
Define locus.
Location of a gene
The locus is crucial for identifying gene positions on chromosomes.
What is a phenotype?
An individual’s observable characteristics (e.g., height, eye color)
The phenotype is the physical expression of a genotype.
What is Mendel’s Principle of Segregation?
During gamete formation, alleles for a trait segregate from each other
This principle explains how offspring inherit one allele from each parent.
What is a dihybrid cross?
Predicts inheritance patterns of two genes that are independent of each other
Dihybrid crosses help in understanding the concept of independent assortment.
What does Mendel’s Principle of Independent Assortment state?
Genes are inherited independently of other genes
This principle applies when genes are located on different chromosomes.
True or False: Genetic linkage means that genes on the same chromosome exhibit independent assortment.
False
Linked genes do not assort independently due to their proximity on the chromosome.
What is incomplete dominance?
Heterozygous genotype displays a unique phenotype that differs from that of homozygous genotypes
An example is the blending of flower colors.
What is codominance?
Heterozygous genotypes simultaneously display multiple phenotypes
An example is AB blood type.
What is pleiotropy?
One gene influences two or more seemingly unrelated phenotypic traits
This concept highlights the complexity of gene functions.
What is a polygenic trait?
Multiple genes contributing to one phenotype
These traits often show a range of phenotypes, such as height.
Fill in the blank: Almost none of the genes in the ______ chromosome have counterparts in the Y chromosome.
X
This difference in gene content impacts sex-linked traits.
What is the expected ratio of XX (female) and XY (male) progeny from random fertilization?
1/2 XX and 1/2 XY
This ratio results from the segregation of sex chromosomes during meiosis.
What are X-linked traits?
Traits whose genes are located on the X chromosome
Males are more likely to express recessive X-linked traits like colorblindness.
What is genetic linkage?
Genes on the same chromosome exhibit linkage and are called linked genes
The closer genes are on a chromosome, the more likely they are to be inherited together.
What does the frequency of gene recombination indicate?
It is used to determine the distance between genes and map their relative locations on a chromosome
Recombination frequency is a key concept in genetic mapping.
What is heritability?
The proportion of variation in a trait that can be attributed to genetic differences
Heritability is often studied using twin studies.
Define concordance in the context of twin studies.
Percentage of cases in which both members of a pair of twins show the trait
High concordance rates indicate a strong genetic influence on traits.
What is regression toward the mean?
The tendency for offspring to resemble the average of their parents rather than the extremes
This concept illustrates the influence of both genetics and environment.
What is a complex trait?
A trait influenced by multiple genes and environmental factors
Examples include height, weight, and susceptibility to diseases.
True or False: Mitochondrial DNA is inherited directly via the maternal lineage with no recombination.
True
This mode of inheritance is crucial for tracing maternal ancestry.
G 1
Pre. synthesis growth
S
Synthesis of DNA via reproduction ; Interphase
G2
Post synthesis growth ; Interphase
Humans have ___ # of chromosomes
23 pairs; total n=46
Prophase (Mitosis)
Chromosomes condenses ; Centrosomes make microtubes + move to polar ends
Pro metaphase (Mitosis )
Microtubes of Microspindles attach to chromosomes
Metaphase (Mitosis)
Chromosomes aline in center of the cell
Anaphase (Mitosis)
sister chromatides pulled apart to poles by Microspindles
Telophase (Mitosis)
theformation of nuclear envelope ; Chromosomes condense.
Prophase I ( Meiosis)
Neclear membrane breaks down ; homologous chromosomes condence
…
non sister chromatinds attach (Bivalent) switch DNA
Prometaphase I (Meiosis)
Microtubes attach to Kinetochores on chromosomes
Metaphase I ( Meiosis )
Pairs line up on equator
Anaphase I (Meiosis)
Homologous Chromosomes seperate ; sister chromatinds stay together
Telophase I (Meiosis)
Two cells form (. cytokinesis)
Meiosis second phase
prophase, Metaphase, Anaphase, telophase
Anaphase - chromosomes pulled apart = cromatids
