Biology Semester 2 Final Review Flashcards

What is Homeostasis?

The maintenance of a stable internal environment.

How does a negative feedback mechanism work when you are in the middle of exercising?

Your body uses a negative feedback mechanism to lower your internal temperature back to normal.

Give an example of a somatic (body) cell:

Skin cell, muscle cell, neuron, etc.

How many chromosomes do somatic (body) cells have?

46

Give an example of a gamete (sex cell):

Sperm or egg cell

How many chromosomes do gametes (sex cells) have?

23

How are gametes different from body cells?

Gametes are sex cells that only have half the number of chromosomes as somatic/body cells.

What happens during the G1 Phase of the cell cycle?

Cell grows and performs its normal functions

What happens during the S Phase of the cell cycle?

DNA is replicated

What happens during the G2 Phase of the cell cycle?

Cell prepares for mitosis

What happens during Mitosis?

Cell divides

What must first happen to a cell before it goes through Mitosis?

DNA must be replicated

Mitosis results in 1 cell splitting into _ daughter cells. Mitosis makes (somatic cells / gametes). The number of chromosomes will be (the same / split in half / doubled) for each daughter cell.

2, somatic cells, the same

Meiosis results in 1 cell splitting into _ daughter cells. Meiosis makes (somatic cells / gametes). The number of chromosomes will be (the same / split in half / doubled) for each daughter cell.

4, gametes, split in half

What is the role of DNA in the cell?

DNA stores genetic information

What are the four nitrogenous bases in DNA?

Adenine, guanine, cytosine, thymine

What are the base-pairs for DNA?

A-T, G-C

RNA has one different nitrogenous base. What is it?

Uracil

A DNA strand undergoing replication contains the bases ACCTAG. Which complementary strand does it produce?

TGGATC

What Amino Acid Sequences do the following mRNA codon sequences code for? CAU - AAA - AUG - CGU

His-Lys-Met-Arg

What Amino Acid Sequences do the following mRNA codon sequences code for? GGG - UCC - ACG - AAA

Gly-Ser-Thr-Lys

What are three ways that bases can be changed during DNA mutations?

Deletion, insertion, substitution

What will ultimately happen after a DNA mutation has occurred?

The protein that DNA codes for will be different, which will change the traits of the organism.

What is crossing-over in Meiosis, and why is it important?

Crossing-over is the exchange of genetic material between homologous chromosomes. It is important because it increases genetic diversity.

What is nondisjunction in Meiosis? What happens to a person when this happens?

Nondisjunction is the failure of chromosomes to separate properly during meiosis. This can lead to a person having too many or too few chromosomes, which can cause genetic disorders.

Give an example of a genotype:

BB, Bb, bb, etc.

Give an example of a phenotype:

Black fur, white fur, blue feathers, etc.

Homozygous Dominant:

BB

Heterozygous:

Bb

Homozygous Recessive:

bb

What are the genotypes of the parents if a heterozygous black chicken mates with a white chicken?

Bb x bb

% chance that the offspring will be white:

50%

% chance that the offspring will be heterozygous:

50%

Total Number of offspring that are heterozygous:

80

If blue feather color (F) is dominant to white feather color (f), what should be the genotypes of the parent birds to produce offspring with blue feathers and offspring with white feathers?

Ff x Ff

How can heterozygous children show incomplete dominance in their traits?

Heterozygous children can show incomplete dominance in their traits when the dominant allele does not completely mask the recessive allele.

How can heterozygous children show codominance in their traits?

Heterozygous children can show codominance in their traits when both alleles are expressed equally.

What are sex-linked traits?

Sex-linked traits are traits that are carried on the sex chromosomes.

What is the main reason why species would need to evolve over time?

Species would need to evolve over time to adapt to changes in their environment.

What are the 4 pieces of evidence for evolution?

Fossil record, comparative anatomy, comparative embryology, molecular biology

How do vestigial (nonfunctional) structures like the appendix or tailbone in humans support the existence of evolution?

Vestigial structures support the existence of evolution because they are remnants of structures that were functional in ancestral species but are no longer functional in modern species.

How does comparing the anatomy of various species support the claim that species share a common ancestor?

Comparing the anatomy of various species supports the claim that species share a common ancestor because it shows that different species have similar structures, which suggests that they evolved from a common ancestor.

What evidence do we have for the existence of supercontinents like Pangaea or Gondwana?

Fossils of the same species have been found on different continents, and the continents fit together like puzzle pieces.

What is an adaptation? Why are they important for species?

An adaptation is a trait that helps a species survive and reproduce in its environment. They are important for species because they allow them to better compete for resources, avoid predators, and reproduce.

How are adaptations related to the idea of natural selection?

Adaptations are related to the idea of natural selection because natural selection is the process by which organisms with favorable adaptations are more likely to survive and reproduce than organisms with less favorable adaptations.

A population of mice has existed in a white sand environment… This is an example of ___ selection.

directional

Define speciation:

Speciation is the process by which new species arise.

How does geographical isolation cause evolution?

Geographical isolation can cause evolution by preventing different populations of the same species from interbreeding. This can lead to the populations diverging genetically and eventually becoming different species.