DAT Biology Comprehensive Review

High-yield flashcards covering key concepts from biology lecture notes, including molecular biology, cell biology, human systems, genetics, and ecology.

What reaction creates a covalent bond between monomers and releases water?

Dehydration (condensation) reaction

Which structural polysaccharide is found in the exoskeletons of arthropods and fungi cell walls?

Chitin

What is the result of hydrogen bonding between the polypeptide backbone, forming $\alpha$-helices or $\beta$-pleated sheets?

Secondary protein structure

How do competitive inhibitors affect the Michaelis Constant ($K_M$) and the maximum reaction velocity ($V_{max}$)?

$K_M$ increases while $V_{max}$ stays the same

What type of fatty acid lacks double bonds and is typically solid at room temperature?

Saturated fatty acids

Which bond type connects the $5'$ phosphate group of one nucleotide to the $3'$ hydroxyl group of another?

Phosphodiester bond

What RNA molecule can act as a non-protein enzyme?

Ribozyme

In the fluid mosaic model, how does cholesterol affect membrane fluidity at high temperatures?

It holds the membrane together and stabilizes it

Which cellular structures facilitate the diffusion of large or charged molecules down their concentration gradient without energy consumption?

Channel proteins (Facilitated transport)

What are the subunits for eukaryotic ribosomes and their total size?

$60S$ and $40S$ subunits forming an $80S$ ribosome

Which organelle is responsible for synthesizing lipids, producing steroid hormones, and detoxifying cells?

Smooth endoplasmic reticulum (Smooth ER)

What enzyme found in peroxisomes breaks down hydrogen peroxide into water and oxygen?

Catalase

Which cytoskeletal component is involved in cyclosis and the formation of the cleavage furrow?

Microfilaments (actin filaments)

Which animal cell junction allows for the passage of ions and small molecules through connexons?

Gap junctions

What happens to a plant cell placed in a hypertonic solution?

It undergoes plasmolysis (cytoplasm shrinks away from the cell wall)

Which process uses one $ATP$ to phosphorylate glucose into glucose-6-phosphate during glycolysis?

Hexokinase

What is the net yield of products from one molecule of glucose at the end of glycolysis?

$2\,ATP$ + $2\,NADH$ + $2\,pyruvate$

Where does the Krebs cycle (Citric Acid Cycle) take place in eukaryotic cells?

Mitochondrial matrix

What is the final electron acceptor in the electron transport chain of aerobic cellular respiration?

Oxygen ($O_2$)

Which anaerobic pathway occurs continuously in red blood cells because they lack mitochondria?

Lactic acid fermentation

Where does beta-oxidation of fatty acids occur in eukaryotic cells?

Mitochondrial matrix

What is the primary enzyme responsible for carbon fixation in the Calvin cycle?

RuBisCo

How do $C_4$ plants prevent photorespiration?

Spatial isolation of $CO_2$ (moving malate to bundle sheath cells)

What factor must be present in adequate amounts for a cell to proceed from the $G_2$ phase into mitosis?

Mitosis promoting factor (MPF)

During which phase of mitosis does the chromosome number double as sister chromatids are pulled apart?

Anaphase

What is the term for the pairing up of homologous chromosomes to form tetrads during prophase I?

Synapsis

Which nitrogenous bases are classified as double-ringed purines?

Adenine (A) and Guanine (G)

Which enzyme is responsible for relieving built-up tension and supercoiling ahead of the replication fork?

Topoisomerase (DNA gyrase)

What is the function of the lac repressor protein in the absence of lactose?

It binds to the operator and blocks transcription

What are the three main post-transcriptional modifications in eukaryotes?

$5'$ capping, $3'$ polyadenylation, and splicing out introns

What is the start codon and the amino acid it codes for?

$AUG$ (Methionine)

What viral life cycle involves the integration of the viral genome into the host's genome without immediate harm?

Lysogenic cycle

Which method of horizontal gene transfer involves a bacteria taking up extracellular DNA from the environment?

Transformation

What is the phenotypic ratio of the $F_2$ generation in a dihybrid cross of two heterozygous individuals?

$$9:3:3:1$$

What occurs when one gene affects the expression of a completely different gene?

Epistasis

Which microscopy technique produces high-resolution $3D$ images of a sample's surface?

Scanning electron microscopy (SEM)

In differential centrifugation, which organelle pellets first due to being the most dense?

Nuclei

What are the three steps of the Polymerase Chain Reaction (PCR)?

Denaturation ($\sim 95^{\circ}C$), Primer annealing ($\sim 65^{\circ}C$), and Elongation ($\sim 70^{\circ}C$)

Which plant tissue transports water and dissolved minerals from roots to leaves using tracheids and vessel elements?

Xylem

What gas is responsible for increasing fruit ripening?

Ethylene

Which plant hormone is produced in response to stress and promotes seed dormancy and stomata closure?

Abscisic acid

What do the vascular bundles look like in a monocot stem compared to a dicot stem?

Scattered in monocots; arranged in a ring in dicots

What is the pathway of blood through the human heart starting from the vena cava?

Right atrium $\rightarrow$ Tricuspid valve $\rightarrow$ Right ventricle $\rightarrow$ Pulmonary semilunar valve $\rightarrow$ Pulmonary arteries $\rightarrow$ Lungs $\rightarrow$ Pulmonary veins $\rightarrow$ Left atrium $\rightarrow$ Bicuspid/Mitral valve $\rightarrow$ Left ventricle $\rightarrow$ Aortic semilunar valve $\rightarrow$ Aorta

What formula calculates Cardiac Output ($CO$)?

$CO = HR \times SV$ (Heart Rate $\times$ Stroke Volume)

Which blood vessels experience the greatest drop in blood pressure?

Arterioles

What are the precursor cells to platelets?

Megakaryocytes

Which fetal structure connects the pulmonary artery to the aorta to bypass the nonfunctional lungs?

Ductus arteriosus

Which lung contains only two lobes to make room for the heart?

The left lung

What five factors cause a right-shift in the oxygen dissociation curve (lowering oxygen affinity)?

Increased $CO_2$, Acid (decreased pH), $2,3-DPG$, Exercise, and increased Temperature (CADET)

Which cell type in the innate immune system releases histamine and heparin in response to injury?

Mast cells

What are the five main types of leukocytes ranked from most to least abundant?

Neutrophils, Lymphocytes, Monocytes, Eosinophils, Basophils (Never Let Monkeys Eat Bananas)

Which class of antibodies is the most abundant in circulation and the only one that can cross the placenta?

IgG

Which part of the neuron is responsible for the summation of graded potentials?

Axon hillock

What is the main inhibitory neurotransmitter of the central nervous system?

Gamma-aminobutyric acid (GABA)

Which brain structure is responsible for memory consolidation?

Hippocampus

What are the two components of the autonomic nervous system?

Sympathetic (fight or flight) and Parasympathetic (rest and digest)

In the sliding filament theory, what binds to troponin to remove tropomyosin from the myosin-binding sites?

$Ca^{2+}$ ions

In a sarcomere, which band represents the entire length of the thick myosin filament?

A band

What is the functional unit of cortical bone composed of multi-layered cylinders?

Osteon (Haversian system)

Which hormone stimulates osteoclasts to increase bone resorption and raise blood calcium levels?

Parathyroid hormone (PTH)

What are the three second messengers used in peptide hormone signaling?

$cAMP$, $IP_3$, and $DAG$

Which cells in the pancreas secrete insulin to lower blood glucose levels?

Beta ($\beta$) cells

What is the pathway of sperm from production to ejaculation?

Seminiferous tubules $\rightarrow$ Epididymis $\rightarrow$ Vas deferens $\rightarrow$ Ejaculatory duct $\rightarrow$ Urethra $\rightarrow$ Penis (SEVEn UP)

Which germ layer gives rise to the central nervous system, epidermis, and adrenal medulla?

Ectoderm

Which extraembryonic structure serves as the first site of blood cell formation in placental mammals?

Yolk sac

What characterizes Gram-positive bacteria after staining?

They stain dark purple and have a thick peptidoglycan layer

According to the $10\%$ rule of energy transfer, what happens to the other $90\%$ of energy between trophic levels?

It is lost as heat

What type of survivorship curve is characteristic of K-selected species like humans?

Type I survivorship curve

What is the difference between kinesis and taxis?

Kinesis is random movement speed change; taxis is directional movement toward or away from a stimulus

What is the term for a non-native species that outcompetes native species and overtakes an ecosystem?

Invasive species