HN Biology Spring Final Exam

Describe how the surface area to volume ratio of a cell changes as the cell grows.

Describe how the surface area to volume ratio of a cell changes as the cell grows.

As the cell grows, the ratio of surface area to volume decreases, but both surface area and volume increase regardless

When is DNA replicated?

S phase of interphase

How many daughter cells are produced by mitosis?

2

How does the DNA in sister chromatids compare?

The same

If a parent cell with 24 chromosomes divides by mitosis how many chromosomes will each daughter cell has?

24

Identify cells in different stages of mitosis.

look at El papel

Identify the purpose of cytokinesis.

Divide up the rest of the cytosol and cell parts during division.

Identify the function of the spindle.

Moves chromosomes to opposite poles during cell division

Describe homologous chromosomes.

A pair of chromosomes that have genes for the same traits at the same location (one is inherited from each parent)

Identify three factors that contribute to genetic variation in organisms.

1. crossing over

2. Independent assortment

3. Random fertilization

What is the main event that occurs during prophase I?

homologous chromosomes pair up, crossing over occurs (non-sister chromosomes trade genes)

What is the main event that occurs during metaphase I?

homologous chromosomes line up at the metaphase plate

What is the main event that occurs during anaphase I?

homologous chromosomes separate and are pulled to opposite poles

What is the main event that occurs during metaphase II?

sister chromatids line up at the metaphase plate

What is the main event that occurs during anaphase II?

sister chromatids separate and are pulled to opposite poles

Identify the components of a DNA nucleotide.

All DNA nucleotides consist of a phosphate group, sugar, and nitrogen-containg base

DNA: Adenine nucleotide, thymine nucleotide, guanine nucleotide, and cytosine nucleotide

RNA: Adenine nucleotide, uracil nucleotide, guanine nucleotide, and cytosine nucleotide

Use Chargaff’s rule to calculate the percentage of each base in an organism’s DNA.

A and T must be the same percentage.

C and G must be the same percentage.

The A, T, C, and G must add up to 100.

Identify the complementary DNA strand to the DNA strand A-C-C-T-G-A-G-A.

T-G-G-A-C-T-C-T

What is the function of DNA polymerase?

adds new nucleotides to the parent strand of DNA

What is the function of helicase?

opens up the double-helix at the replication forks

Where does the replication occur in a eukaryotic cell?

Nucleus

What direction does the lagging strand go?

Away from the replication fork

How many primers does the lagging strand have?

Multiple

What are Okazaki fragments?

A series of short segments of DNA that make up a lagging strand

What direction does the leading strand go?

Toward the replication fork

How many primers does the leading strand have?

Single

Describe the function of mRNA.

carries information from DNA in the nucleus to ribosomes in the cytoplasm

Describe the function of tRNA.

carries amino acids to ribosomes by the messages from the mRNA

Describe the function of RNA polymerase.

transcribes a mRNA from a DNA template

Where does transcription occur in a eukaryotic cell?

Nucleus

How many nucleotides are in a codon?

3

Identify three ways that pre-mRNA is edited.

1. A 5’ cap is added to the 5’ end

2. A poly-A tail is added to the 3’ end

3. Introns are cut out, exons are spliced together

Identify the sequence of information transfer in all organisms.

DNA —> mRNA —> polypeptide

Where does translation occur in a eukaryotic cell?

Cytoplasm

Define homozygous dominant.

Both alleles are the same and dominant.

Ex. TT

Define homozygous recessive.

Both alleles are the same and recessive.

Ex. tt

Define heterozygous.

when the two alleles are different

Ex. Tt

Define dominant.

are always expressed if inherited

Define recessive.

only expressed when an organism inherits a recessive allele from both parents

Define allele.

alternative form of a gene

Define phenotype.

observable characteristics

Define genotype.

the pair of alleles for a characteristic

What is the Principle of Dominance?

some alleles are dominant and others are recessive

What is the Principle of Segregation?

during gamete formation, the two alleles for each gene separate from each other, so that each sex cell (gamete) carries only one allele for each gene

What is the Principle of Independent Assortment?

genes for different traits separate independently during the formation of gametes (assuming that the genes are on different chromosomes)

incomplete dominance

the phenotype of heterozygous organisms is somewhere between the phenotypes of the two homozygous varieties

Ex. RR red body x WW white body = RW pink body

multiple alleles

there are more than 2 alleles for a trait

Ex. I^A, I^B, i

codominance

two dominant alleles are both expressed

Ex. type I^A and I^B = I^AB

epistasis

when the phenotypic expression of one gene is influenced by another gene

Ex. coat color in labradors

polygenic inheritance

occurs when two or more genes have an additive effect on a single phenotype

Ex. Human skin color is influenced by 3 different genes

Identify an example of the environment influencing the phenotype of an organism.

Hydrangea flowers of the same genotype, range from blue-violet to pink depending on the soil acidity

Identify 4 characteristics of bacteria that are different from most eukaryotic organisms.

1. no nucleus

2. no cell parts with membranes around them

3. they have a cell wall

4. much smaller than eukaryotes

Identify and describe the structural parts of a virus

Viruses have DNA or RNA surrounded by a protein capsid

Identify 5 functions of the lymphatic system.

1. to remove excess tissue fluid

2. absorbing nutrients

3. destroy pathogens in the lymph nodes

4. lymph vessels have valves that prevent the backflow of lymph

5. skeletal muscles help more lymph through the lymph vessels

Define the term pathogen.

an agent that causes infectious disease

Identify 5 ways infectious diseases spread.

1. Droplets in the air

2. Physical contact

3. Exchange of body fluids

4. Contaminated food or water

5. Infection by animals

Identify 5 examples of innate or nonspecific first line defenses.

1. skin

2. mucus

3. tears

4. saliva

5. gastric juice

What is the humoral response?

B cells provide immunity against antigens and pathogens in body fluids (blood plasma, tissue fluid, and lymph)

What is the cell-mediated response?

T cells attack cells infected with viruses and cancerous cells

Identify the type of white blood cell that makes antibodies.

plasma cells

Natural active

you make your own antibodies and you do not get a shot

Ex. your body fights pathogens the normal way

Artificial active

you make your own antibodies and you get a shot

Ex. both fighters fight

Natural passive

you get antibodies from another organism and you don’t get a shot

Ex. mom giving nutrients to you through breastmilk

Artificial passive

you get antibodies from another organism and you get a shot

ex. just getting a shot