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  <xsd:element id="bcab_IssuanceOfConvertiblePreferredStockForCashShares" name="IssuanceOfConvertiblePreferredStockForCashShares" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_IssuanceOfConvertiblePreferredStockForCashValue" name="IssuanceOfConvertiblePreferredStockForCashValue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="bcab_LeaseLiability" name="LeaseLiability" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="bcab_LesseeOperatingLeaseLiabilityMinimumPaymentsDue" name="LesseeOperatingLeaseLiabilityMinimumPaymentsDue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="bcab_LesseeOperatingLeaseLiabilityMinimumPaymentsDueInFourYears" name="LesseeOperatingLeaseLiabilityMinimumPaymentsDueInFourYears" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="bcab_LesseeOperatingLeaseLiabilityMinimumPaymentsDueInThreeYears" name="LesseeOperatingLeaseLiabilityMinimumPaymentsDueInThreeYears" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="bcab_LesseeOperatingLeaseLiabilityMinimumPaymentsDueInTwelveMonths" name="LesseeOperatingLeaseLiabilityMinimumPaymentsDueInTwelveMonths" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="bcab_LesseeOperatingLeaseLiabilityMinimumPaymentsDueInTwoYears" name="LesseeOperatingLeaseLiabilityMinimumPaymentsDueInTwoYears" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="bcab_LesseeOperatingLeaseLiabilityPaymentsDueThereafter" name="LesseeOperatingLeaseLiabilityPaymentsDueThereafter" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="bcab_LessorOperatingLeasesOptionToExtend" name="LessorOperatingLeasesOptionToExtend" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_LiabilityToLicensor" name="LiabilityToLicensor" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="bcab_LicenseAndOptionAgreementPayment" name="LicenseAndOptionAgreementPayment" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="bcab_LicenseFees" name="LicenseFees" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="bcab_LicenseTerminationInformationDescription" name="LicenseTerminationInformationDescription" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_LongTermAccruedInterest" name="LongTermAccruedInterest" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="bcab_LumpSumSalaryPaymentAndTargetBonus" name="LumpSumSalaryPaymentAndTargetBonus" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="bcab_MinimumPerShareAmountOfConvertiblePreferenceSharesLiquationPreference" name="MinimumPerShareAmountOfConvertiblePreferenceSharesLiquationPreference" type="dtr-types:perShareItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_NetIncomeLossAllocableToClassCPreferredUnitHolders" name="NetIncomeLossAllocableToClassCPreferredUnitHolders" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="bcab_NetIncomeLossConsolidatedNetLossAndComprehensiveLoss" name="NetIncomeLossConsolidatedNetLossAndComprehensiveLoss" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="bcab_NetLossOfHTKYAllocatedToNoncontrollingInterest" name="NetLossOfHTKYAllocatedToNoncontrollingInterest" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="bcab_NumberOfAcceleratedFullVestingEquityAwardsIncludingRestrictedStockUnits" name="NumberOfAcceleratedFullVestingEquityAwardsIncludingRestrictedStockUnits" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_NumberOfAcceleratedFullVestingEquityAwardsIncludingStockOptions" name="NumberOfAcceleratedFullVestingEquityAwardsIncludingStockOptions" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_NumberOfSharesHeldOfOutstandingHTKYPreferredEquity" name="NumberOfSharesHeldOfOutstandingHTKYPreferredEquity" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_OperatingLeaseRightOfUseAssetTotal" name="OperatingLeaseRightOfUseAssetTotal" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="bcab_OperatingLossCarryforwardsExpirationPeriod" name="OperatingLossCarryforwardsExpirationPeriod" type="xbrli:gYearItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_OptionsGrantsRelatedToRoyaltyPaymentPeriod" name="OptionsGrantsRelatedToRoyaltyPaymentPeriod" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_OptionsGrantsRelatedToRoyaltyPaymentsPeriod" name="OptionsGrantsRelatedToRoyaltyPaymentsPeriod" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_OrphanDrugCredit" name="OrphanDrugCredit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="bcab_OrphanDrugCreditCarryforwardsExpirationPeriod" name="OrphanDrugCreditCarryforwardsExpirationPeriod" type="xbrli:gYearItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_OtherIncomeExpense" name="OtherIncomeExpense" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="bcab_OtherPrepaidExpensesAndCurrentAssets" name="OtherPrepaidExpensesAndCurrentAssets" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="bcab_OutstandingAndExercisableCommonStockWarrants" name="OutstandingAndExercisableCommonStockWarrants" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_OutstandingAndExpiredCommonStockWarrants" name="OutstandingAndExpiredCommonStockWarrants" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_PartnershipIncomeNotSubjectToTax" name="PartnershipIncomeNotSubjectToTax" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="bcab_PeriodRelatedToChangingOfOwnershipLimitationPercentageDesignatedByClassBCommonStockHolder" name="PeriodRelatedToChangingOfOwnershipLimitationPercentageDesignatedByClassBCommonStockHolder" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_PreferredReturnOnClassAdjsutmentsIncreaseDecrease" name="PreferredReturnOnClassAdjsutmentsIncreaseDecrease" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="bcab_PrepaidResearchAndDevelopmentExpense" name="PrepaidResearchAndDevelopmentExpense" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="bcab_ProceedsFromThePrivatePlacementNetOfUnderwritingDiscountsAndCommissionsAndOtherOfferingCosts" name="ProceedsFromThePrivatePlacementNetOfUnderwritingDiscountsAndCommissionsAndOtherOfferingCosts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="bcab_PromissoryNotesPayableToAggregatePrincipalAmount" name="PromissoryNotesPayableToAggregatePrincipalAmount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="bcab_PurchasedOfMinorityShareholdersOrdinaryShares" name="PurchasedOfMinorityShareholdersOrdinaryShares" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_ReductionToAggregateProfitsInterestLiability" name="ReductionToAggregateProfitsInterestLiability" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="bcab_ReimbursementOfManufacturingCosts" name="ReimbursementOfManufacturingCosts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="bcab_ResearchAndDevelopmentExpenseRelatedParty" name="ResearchAndDevelopmentExpenseRelatedParty" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="bcab_ScheduleOfLesseeOperatingAnnualMinimumPaymentsLeaseLiabilityMaturityTableTextBlock" name="ScheduleOfLesseeOperatingAnnualMinimumPaymentsLeaseLiabilityMaturityTableTextBlock" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsShares" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsShares" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_ShareBasedCompensationArrangementByShareBasedPaymentAwardUnvestedFairValueAssumptionsShares" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardUnvestedFairValueAssumptionsShares" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_SharesAvailableForAwardsDescription" name="SharesAvailableForAwardsDescription" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_StockBasedCompensationExpenseAndAdditionalPaidInCapitalRelatedToFairValueOfUnvestedLiability" name="StockBasedCompensationExpenseAndAdditionalPaidInCapitalRelatedToFairValueOfUnvestedLiability" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="bcab_StockIssuedDuringPeriodSharesConversionOfConvertiblePreferredStockIntoCommonStock" name="StockIssuedDuringPeriodSharesConversionOfConvertiblePreferredStockIntoCommonStock" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_StockIssuedDuringPeriodSharesConversionOfSeriesDConvertiblePreferredStockIntoCommonStock" name="StockIssuedDuringPeriodSharesConversionOfSeriesDConvertiblePreferredStockIntoCommonStock" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_StockIssuedDuringPeriodSharesConversionOfStock" name="StockIssuedDuringPeriodSharesConversionOfStock" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_StockIssuedDuringPeriodValueConversionOfConvertiblePreferredStockIntoCommonStock" name="StockIssuedDuringPeriodValueConversionOfConvertiblePreferredStockIntoCommonStock" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="bcab_StockIssuedDuringPeriodValueConversionOfSeriesDConvertiblePreferredStockIntoCommonStock" name="StockIssuedDuringPeriodValueConversionOfSeriesDConvertiblePreferredStockIntoCommonStock" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="bcab_StockIssuedDuringPeriodValueLLCConversion" name="StockIssuedDuringPeriodValueLLCConversion" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="bcab_SubsequentSaleOfConvertiblePreferredStockToNewInvestorsShares" name="SubsequentSaleOfConvertiblePreferredStockToNewInvestorsShares" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_TaxRelatedToNetSettlementOfEquityAwardsIncludedInAccountsPayableAndAccruedExpenses" name="TaxRelatedToNetSettlementOfEquityAwardsIncludedInAccountsPayableAndAccruedExpenses" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="bcab_UnallocatedSharebasedCompensationExpense" name="UnallocatedSharebasedCompensationExpense" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="bcab_UncertainTaxPositionsPercentage" name="UncertainTaxPositionsPercentage" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="bcab_UpfrontNonRefundablePayment" name="UpfrontNonRefundablePayment" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="bcab_WarrantsExpiredAndUnexercised" name="WarrantsExpiredAndUnexercised" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_WarrantsForThePurchaseOfCommonStock" name="WarrantsForThePurchaseOfCommonStock" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_OrganizationAndSummaryOfSignificantAccountingPoliciesLineItems" name="OrganizationAndSummaryOfSignificantAccountingPoliciesLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="bcab_AmendedBeiGeneCollaborationMember" name="AmendedBeiGeneCollaborationMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="bcab_BioAtlaHoldingsLLCMember" name="BioAtlaHoldingsLLCMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="bcab_BioDuroMember" name="BioDuroMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="bcab_ClassCPreferredUnitMember" name="ClassCPreferredUnitMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="bcab_ClassDMember" name="ClassDMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="bcab_CommonSockOtionsMember" name="CommonSockOtionsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="bcab_CommonSockWrantsMember" name="CommonSockWrantsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="bcab_CustomerMember" name="CustomerMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="bcab_DecemberSeventyTwoThousandTwentyOneMember" name="DecemberSeventyTwoThousandTwentyOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="bcab_EmployeesStockPurchasePlanMember" name="EmployeesStockPurchasePlanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="bcab_EXUMABiotechCorpAndSubsidiaryMember" name="EXUMABiotechCorpAndSubsidiaryMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="bcab_FurnitureFixturesAndOfficeEquipmentMember" name="FurnitureFixturesAndOfficeEquipmentMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="bcab_HimalayaParentLLCMember" name="HimalayaParentLLCMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="bcab_HimalayaTherapeuticsSEZCMember" name="HimalayaTherapeuticsSEZCMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="bcab_InversagenLLCMember" name="InversagenLLCMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="bcab_JayShortAndCarolynAndersonShortMember" name="JayShortAndCarolynAndersonShortMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="bcab_LaboratoryEquipmentMember" name="LaboratoryEquipmentMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="bcab_MarchTwelveTwoThousandTwentyTwoMember" name="MarchTwelveTwoThousandTwentyTwoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="bcab_MsShortMember" name="MsShortMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="bcab_OtherAccruedExpensesMember" name="OtherAccruedExpensesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="bcab_PaycheckProtectionProgramMember" name="PaycheckProtectionProgramMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="bcab_PfizerIncMember" name="PfizerIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="bcab_PfizerNotesMember" name="PfizerNotesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="bcab_PostDivisionSuccessorMember" name="PostDivisionSuccessorMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="bcab_PPPLoanMember" name="PPPLoanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="bcab_PrivatePlacementOfCommonStockMember" name="PrivatePlacementOfCommonStockMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="bcab_SeriesBConvertiblePreferenceSharesMember" name="SeriesBConvertiblePreferenceSharesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="bcab_SeriesDConvertiblePreferredStockMember" name="SeriesDConvertiblePreferredStockMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="bcab_SeriesDConvertiblePreferredStokMember" name="SeriesDConvertiblePreferredStokMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="bcab_TwoThousandAndNineteenNoteMember" name="TwoThousandAndNineteenNoteMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="bcab_TwoThousandAndTwentyNoteMember" name="TwoThousandAndTwentyNoteMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="bcab_TwoThousandEighteenNotesMember" name="TwoThousandEighteenNotesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="bcab_TwoThousandNineteenMember" name="TwoThousandNineteenMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="bcab_TwoThousandTwentyEquityIncentivePlanMember" name="TwoThousandTwentyEquityIncentivePlanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="bcab_TwoThousandTwentyMember" name="TwoThousandTwentyMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="bcab_TwoThousandTwentyPlanMember" name="TwoThousandTwentyPlanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="bcab_UnsecuredConvertiblePromissoryNoteMember" name="UnsecuredConvertiblePromissoryNoteMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="bcab_WarrantsMember" name="WarrantsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="bcab_CorporateReorganizationAndFinancingPolicyTextBlock" name="CorporateReorganizationAndFinancingPolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_LiquidityAndGoingConcernPolicyTextBlock" name="LiquidityAndGoingConcernPolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_OrganizationPolicyTextBlock" name="OrganizationPolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_PrinciplesOfConsolidationAndDeconsolidationPolicyTextBlock" name="PrinciplesOfConsolidationAndDeconsolidationPolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_OrganizationAndSummaryOfSignificantAccountingPoliciesTable" name="OrganizationAndSummaryOfSignificantAccountingPoliciesTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="bcab_ScheduleOfCommonStockReservedForFutureIssuanceTableTextBlock" name="ScheduleOfCommonStockReservedForFutureIssuanceTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_ScheduleOfPrepaidExpensesOtherCurrentAssetsTableTextBlock" name="ScheduleOfPrepaidExpensesOtherCurrentAssetsTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_AccountingForDerivativesPolicyPolicyTextBlock" name="AccountingForDerivativesPolicyPolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_AllocationOfEquityBasedCompensationForClassBUnitsTableTextBlock" name="AllocationOfEquityBasedCompensationForClassBUnitsTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_BeneficialConversionFeaturesPolicyPolicyTextBlock" name="BeneficialConversionFeaturesPolicyPolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_CollaborationLicenseAndOptionAgreementTextBlock" name="CollaborationLicenseAndOptionAgreementTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_EXUMABiotechCorpTextBlock" name="EXUMABiotechCorpTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_LeaseAccountingPriorToTheAdoptionOfAsc842PolicyPolicyTextBlock" name="LeaseAccountingPriorToTheAdoptionOfAsc842PolicyPolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_ProfitsInterestIncentivePlanTextBlock" name="ProfitsInterestIncentivePlanTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_ReverseStockSplitPolicyTextBlock" name="ReverseStockSplitPolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_ScheduleOfLesseeOperatingAnnualMinimumPaymentLeaseLiabilityMaturityTableTextBlock" name="ScheduleOfLesseeOperatingAnnualMinimumPaymentLeaseLiabilityMaturityTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_ScheduleOfProfitInterestLiabilityReconciliationTableTextBlock" name="ScheduleOfProfitInterestLiabilityReconciliationTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="bcab_ScheduleOfSupplementalBalanceSheetInformationRelatedToLeaseLiabilitiesTableTextBlock" name="ScheduleOfSupplementalBalanceSheetInformationRelatedToLeaseLiabilitiesTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
</xsd:schema>
