Inheritance
What is a phenotype?
This term describes the observable form of a trait, such as purple flowers.
What is asexual reproduction?
This type of reproduction involves one parent and no fusion of gametes, usually producing genetic clones.
What are A–T and C–G?
These are the two correct DNA base-pair combinations.
What are amino acids?
These building blocks join together to form proteins.
What are weathering, erosion and deposition, respectively?
These three processes break rock into pieces, move the pieces and finally drop them in a new location.
What are alleles?
Different versions of the same gene, such as B and b, are called these.
What is a zygote with 46 chromosomes?
A human sperm and egg each contain 23 chromosomes. Their fusion produces this cell with this total number of chromosomes.
What is helicase?
This enzyme separates the two DNA strands by breaking the hydrogen bonds between them.
What is transcription?
This process uses a DNA template to make mRNA in the nucleus of a eukaryotic cell.
What are igneous, sedimentary and metamorphic rocks?
Cooling lava, compacted and cemented sediment, and rock changed by heat and pressure without melting form these three rock types, respectively.
What is heterozygous?
An organism with genotype Bb has this type of allele combination.
What are binary fission and vegetative propagation, respectively?
A bacterium copies its DNA and splits into two cells. A strawberry plant produces a new plant from a runner. These are the two asexual methods.
What are DNA polymerase and ligase, respectively?
One enzyme adds complementary DNA nucleotides and proofreads. Another joins short DNA fragments. Name both.
What is a ribosome?
This cell structure reads mRNA codons and joins amino acids during translation.
What is an angular unconformity?
Horizontal sedimentary layers lie above older tilted layers, with a gap in the rock record between them. This is the type of unconformity shown.
What is an allele that can affect the phenotype when only one copy is present?
Dominant Allele
What are pollination, followed by fertilisation?
These two different processes occur when pollen reaches a stigma and, later, a male gamete fuses with a female gamete in an ovule.
What are one original strand and one newly built strand?
DNA replication is called “semi-conservative” because each completed DNA molecule contains these two strands.
What is tRNA?
This RNA molecule carries an amino acid and has an anticodon that pairs with an mRNA codon.
What is an index fossil?
This type of fossil is useful for matching the ages of rock layers because its species was widespread, abundant and lived for a short time.
What is 25% (¼)? The possible genotypes are BB, Bb, Bb and bb.
In a cross between Bb and Bb, where B is completely dominant, this is the probability that an offspring will show the recessive phenotype.
What is greater genetic variation, increasing the chance that some individuals have alleles that help them survive and reproduce?
When a new disease appears, a sexually reproducing population may have a survival advantage for this reason.
Both DNA strands are copied at the same time, but one is copied continuously while the other is copied in short fragments. Explain why, and name the enzyme that joins the fragments.
The template strands run in opposite directions, but DNA polymerase builds new DNA only in the 5′ → 3′ direction. Therefore, the leading strand is copied continuously toward the replication fork, while the lagging strand is copied in fragments. Ligase joins these fragments
What is AUG–CCU–GAA?
A DNA template is read in this order: TAC–GGA–CTT. This is the complementary mRNA sequence.
What is A → B → intrusion, using superposition and cross-cutting relationships?
Undisturbed sedimentary layer A lies below layer B. An igneous intrusion cuts through both. Put A, B and the intrusion in order from oldest to youngest, and name the two principles used.